🧪 Chemistry · Class 11 · NEET & JEE
Hydrogen - Practice Questions with Answers 75 free MCQs on Hydrogen, each with its own worked answer and explanation. The simplest and most abundant element in the universe. Study its unique position in the periodic table, isotopes (protium, deuterium, tritium), properties of water and hydrogen peroxide, and industrial uses.
Take the timed Hydrogen chapterwise test → 75 practice questions on Hydrogen , sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Hydrogen notes .
Hydrogen Bonding Network in Water O H H O H H O H H O H H Dashed green lines = hydrogen bonds (weaker than O-H covalent bonds) Each water molecule's O-H bonds (covalent, solid) can hydrogen-bond (dashed) to neighbouring molecules, forming an extended network responsible for water's unusually high boiling point and density anomaly.
Easy - 25 questions Q1.
Hydrogen resembles the halogens (Group 17) in which one of these respects?
A It is one electron short of a noble-gas shellB It forms strongly basic oxides on combustionC It has a very low ionisation enthalpy like themD It exists as a liquid at room temperatureShow answer & explanation →
Q2.
Which of the following is classified as an electron-deficient hydride?
A Methane, CH<sub>4</sub>B Diborane, B<sub>2</sub>H<sub>6</sub>C Water, H<sub>2</sub>OD Ammonia, NH<sub>3</sub>Show answer & explanation →
Q3.
Which element has the greatest tendency to form covalent molecular hydrides?
A Sodium, a reactive s-block metalB Calcium, an alkaline earth metalC Carbon, a p-block non-metalD Potassium, a soft alkali metalShow answer & explanation →
Q4.
Why is dihydrogen relatively unreactive at ordinary room temperature?
A It spontaneously ionises to give H<sup>+</sup>B Its molecules are strongly polarC It has a very high electron affinityD Its H–H bond enthalpy is very highShow answer & explanation →
Q5.
Hydrogen peroxide is stored in wax-lined bottles kept in the dark because:
A Light and rough surfaces catalyse its decompositionB It is very volatile and evaporates fastC It reacts violently with the silica in glassD It freezes very readily near room temperatureShow answer & explanation →
Q7.
How many isotopes does hydrogen have?
A 3 (protium, deuterium, tritium)B 2, counting only protium and deuteriumC 4, including a hypothetical quadrium isotopeD 1, since hydrogen has no other known isotopesShow answer & explanation →
Q8.
Heavy water is:
A D<sub>2</sub>O (deuterium oxide)B H<sub>2</sub>O<sub>2</sub>C H<sub>2</sub>O with saltsD Tritium waterShow answer & explanation →
Q9.
Hydrogen gas is produced in the laboratory by:
A Reaction of zinc with dilute sulfuric acidB Simple electrolysis of pure water without any added electrolyteC Direct heating of water to its boiling pointD Mixing solid NaOH pellets with cold waterShow answer & explanation →
Q10.
Which process is used industrially to produce hydrogen from natural gas?
A Steam reformingB Haber processC Contact processD Hall processShow answer & explanation →
Q14.
Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is a powerful:
A Oxidising agentB Reducing agent onlyC AcidD BaseShow answer & explanation →
Q16.
Hard water contains dissolved salts of:
A Calcium and magnesiumB Sodium and potassiumC Iron and copperD Sodium chloride onlyShow answer & explanation →
Q17.
Temporary hardness of water is caused by:
A Ca(HCO<sub>3</sub>)<sub>2</sub> and Mg(HCO<sub>3</sub>)<sub>2</sub>B CaSO<sub>4</sub> and MgSO<sub>4</sub> as generally observedC CaCl<sub>2</sub> and MgCl<sub>2</sub> in typical laboratory settingsD NaCl under usual circumstancesShow answer & explanation →
Q18.
Permanent hardness of water is caused by:
A CaSO<sub>4</sub>, MgSO<sub>4</sub>, CaCl<sub>2</sub>, MgCl<sub>2</sub>B Ca(HCO<sub>3</sub>)<sub>2</sub> according to most researchersC Carbonate salts in the majority of cases studiedD NaHCO<sub>3</sub> as widely reportedShow answer & explanation →
Q19.
Which method removes both temporary and permanent hardness?
A Ion exchange methodB BoilingC Distillation of a small amountD Addition of Na<sub>2</sub>CO<sub>3</sub>Show answer & explanation →
Q20.
H<sub>2</sub>O<sub>2</sub> decomposes on exposure to light to give:
A H<sub>2</sub>O and O<sub>2</sub>B H<sub>2</sub> and O<sub>2</sub>C H<sub>2</sub> and H<sub>2</sub>OD HO<sub>2</sub> and HShow answer & explanation →
Q21.
Hydrogen is used as a fuel because:
A It has very high calorific value and burns cleanlyB It is currently the cheapest fuel available on the marketC It exists as a stable solid at room temperatureD It is classified as a non-flammable gasShow answer & explanation →
Q22.
Which type of hydride is formed by alkali metals?
A Ionic (saline) hydridesB Covalent hydridesC Interstitial hydridesD Polymeric hydridesShow answer & explanation →
Q23.
Water has an unusually high boiling point (100°C) due to:
A Extensive hydrogen bondingB High atomic massC Ionic characterD Large molecular sizeShow answer & explanation →
Q25.
Which of the following is NOT an isotope of hydrogen?
A Helium, the noble gas with two protons and two neutrons in its common isotopeB Protium, the most abundant isotope with one proton and no neutrons in standard practiceC Deuterium, the isotope with one proton and one neutron under most conditions encounteredD Tritium, the radioactive isotope with one proton and two neutrons as frequently observed in practiceShow answer & explanation →
Medium - 25 questions Q26.
In 2MnO<sub>4</sub><sup>-</sup> + 5H<sub>2</sub>O<sub>2</sub> + 6H<sup>+</sup> → 2Mn<sup>2+</sup> + 5O<sub>2</sub> + 8H<sub>2</sub>O, hydrogen peroxide behaves as a:
A Oxidising agent, its oxygen going -1 to -2B Reducing agent, its oxygen going from -1 to 0C Catalyst that stays chemically unchangedD Simple dehydrating agent in this mediumShow answer & explanation →
Q27.
A hydrogen peroxide sample marked '10 volume' means that:
A It contains 10 g of H<sub>2</sub>O<sub>2</sub> per litreB It is a 10 molar solution of H<sub>2</sub>O<sub>2</sub>C 1 mL gives 10 mL of O<sub>2</sub> at STP on decayD It is exactly 10% H<sub>2</sub>O<sub>2</sub> by massShow answer & explanation →
Q28.
The catalytic reaction CO + 2H<sub>2</sub> → CH<sub>3</sub>OH is used industrially to manufacture:
A Ethylene glycolB FormaldehydeC Acetic acidD MethanolShow answer & explanation →
Q29.
Assertion: The two O–H bonds of H<sub>2</sub>O<sub>2</sub> do not lie in one plane. Reason: It has an open-book (non-planar) structure.
A Both true and the reason explains itB Both true but reason does not explain itC Assertion false but reason is trueD Assertion true but the reason is falseShow answer & explanation →
Q30.
Which statement about the three isotopes of hydrogen is correct?
A They differ in their number of protonsB Protium, deuterium, tritium have 0,1,2 neutronsC They each contain the same neutron countD Tritium is the most abundant in natureShow answer & explanation →
Q31.
The water-gas shift reaction is:
A CO + H<sub>2</sub>O → CO<sub>2</sub> + H<sub>2</sub>B CH<sub>4</sub> + H<sub>2</sub>O → CO + H<sub>2</sub>C C + H<sub>2</sub>O → CO + H<sub>2</sub>D 2H<sub>2</sub>O → 2H<sub>2</sub> + O<sub>2</sub>Show answer & explanation →
Q32.
Which compound acts as both oxidising and reducing agent?
A H<sub>2</sub>O<sub>2</sub>B HClC H<sub>2</sub>SO<sub>4</sub>D HNO<sub>3</sub>Show answer & explanation →
Q33.
The concentration of H<sub>2</sub>O<sub>2</sub> is expressed in:
A Volume strength (V10, V20) based on O<sub>2</sub> liberatedB The fixed molar mass value of the H<sub>2</sub>O<sub>2</sub> moleculeC The measured pH of the aqueous solutionD The bulk density of the solution aloneShow answer & explanation →
Q34.
Bleaching by H<sub>2</sub>O<sub>2</sub> is due to its:
A Oxidising action (releases nascent oxygen)B Reducing action that decolourises dyes by hydrogenationC Its mildly acidic nature lowering the solution's pHD Its mildly alkaline nature raising the solution's pHShow answer & explanation →
Q35.
The reaction H<sub>2</sub>O<sub>2</sub> + KI → I<sub>2</sub> + KOH + H<sub>2</sub>O demonstrates H<sub>2</sub>O<sub>2</sub> acting as:
A Oxidising agent (oxidises I- to I<sub>2</sub>)B Reducing agent in the majority of cases studiedC Both oxidant and reductant as widely reportedD Neutral catalyst in standard practiceShow answer & explanation →
Q36.
Why does ice float on water?
A Water at 4°C is densest; ice has open hydrogen-bonded lattice making it less dense than liquid waterB Solid ice molecules acquire a higher effective molecular weight than liquid water molecules under most conditions encounteredC Liquid water expands mainly very slightly in volume as it approaches 0°C as frequently observed in practiceD Ice is held together largely by weak van der Waals forces rather than hydrogen bonds in many documented casesShow answer & explanation →
Q37.
The softening of water by Clark's method involves adding:
A Slaked lime Ca(OH)<sub>2</sub> to remove temporary hardness by precipitating CaCO<sub>3</sub>B Washing soda (Na<sub>2</sub>CO<sub>3</sub>) to precipitate both temporary and permanent hardnessC A synthetic ion exchange resin that swaps Ca<sup>2+</sup> for Na+D Alum, which coagulates suspended colloidal clay particlesShow answer & explanation →
Q38.
The Permutit process uses which substance to soften water?
A Sodium aluminium silicate (zeolite/permutit) ion exchangerB Activated charcoal that adsorbs dissolved calcium and magnesium ionsC A combined lime-and-soda treatment to precipitate both hardness typesD Simple distillation to vaporise and recondense the pure waterShow answer & explanation →
Q39.
Interstitial hydrides are formed by:
A d and f block transition metals (e.g., Pd, La) absorbing H<sub>2</sub> into lattice gapsB Alkali metals forming stoichiometric ionic hydride salts according to conventional understandingC Non-metals forming covalent molecular hydrides in routine practice overallD Noble gases trapping hydrogen within clathrate cages in most cases under typical conditionsShow answer & explanation →
Q40.
The Haber process produces ammonia from:
A N<sub>2</sub> and H<sub>2</sub> (using Fe catalyst, high pressure, 400-500°C)B N<sub>2</sub> and O<sub>2</sub> combined catalytically over a platinum gauzeC CH<sub>4</sub> and N<sub>2</sub> reacted directly at moderate pressureD NH<sub>3</sub> itself recycled through a secondary catalytic loopShow answer & explanation →
Q41.
What is syngas?
A A mixture of CO and H<sub>2</sub> produced from steam reforming of hydrocarbonsB Pure hydrogen gas obtained after fractional separationC A mixture of methane and hydrogen used directly as a fuel blendD A mixture of carbon dioxide and water vapour from combustionShow answer & explanation →
Q42.
The bond dissociation energy of H<sub>2</sub> is approximately:
A 436 kJ/molB 946 kJ/molC 240 kJ/molD 154 kJ/molShow answer & explanation →
Q43.
H<sub>2</sub>O<sub>2</sub> structure has a dihedral angle of about 111° in the gas phase because:
A Lone pair repulsion on oxygen atoms causes non-planar structureB Both O-H bonds being chemically equivalent forces a planar geometryC Ordinary water adopts an identical open-book dihedral structureD The O-O linkage is actually a triple bond restricting rotationShow answer & explanation →
Q44.
Nascent hydrogen is:
A Highly reactive atomic hydrogen formed in situ (not H<sub>2</sub> gas)B Ordinary H<sub>2</sub> gas simply compressed to high pressureC Deuterium gas generated by electrolysis of heavy waterD Pure protium gas isolated from natural hydrogenShow answer & explanation →
Q45.
The ortho and para forms of dihydrogen differ in:
A Relative nuclear spin orientation of the two H nuclei (parallel vs antiparallel)B The precisely measured H-H bond length within each form of the moleculeC The overall H-H bond dissociation energy required to break the molecule apartD Their isotope composition, with the para form containing deuterium insteadShow answer & explanation →
Q46.
H<sub>2</sub>O<sub>2</sub> acts as a reducing agent when it reacts with:
A Acidified KMnO<sub>4</sub> (a stronger oxidising agent)B Iodide ion, which it oxidises to free iodineC Fe<sup>2+</sup>, which it oxidises to Fe<sup>3+</sup>D Cl<sub>2</sub> gas, which it reduces to chloride ionShow answer & explanation →
Q47.
What percentage concentration is commercial H<sub>2</sub>O<sub>2</sub>?
A 3% (household), 30% (laboratory), 90%+ (industrial/rocket fuel)B Usually supplied as pure 100% anhydrous liquid according to standard textbooksC Fixed at 1% concentration for all commercial uses in general practiceD A single standard grade of 50% for every application as frequently describedShow answer & explanation →
Q48.
Calgon (sodium hexametaphosphate) softens water by:
A Forming soluble complexes with Ca<sup>2+</sup> and Mg<sup>2+</sup> ions (sequestration)B Precipitating the calcium and magnesium ions as insoluble saltsC Exchanging the hardness ions for sodium ions on a resin bedD Removing the hardness ions through simple distillationShow answer & explanation →
Q49.
Liquid hydrogen is used as:
A Rocket fuel (cryogenic propellant)B A substitute for drinking water in emergency suppliesC A high-temperature lubricant for industrial machineryD A solid electrode material in galvanic cellsShow answer & explanation →
Q50.
The dielectric constant of water (80) is much higher than most solvents because:
A Strong hydrogen bonding creates a highly ordered, polar medium that stabilises ions effectivelyB Water generally has a higher physical density than most organic solvents in most textbook accountsC Water molecules are unusually small compared to other solvent molecules during normal conditionsD Water is largely colourless and transparent to visible light as generally observed in typical laboratory settingsShow answer & explanation →
Hard - 25 questions Q51.
A hydrogen peroxide solution is labelled '20 volume'. Its percentage strength (w/v) is closest to:
A About 12 percentB About 3 percentC About 6 percentD About 30 percentShow answer & explanation →
Q52.
H<sub>2</sub>O<sub>2</sub> liberates iodine from acidified KI yet decolourises acidified KMnO<sub>4</sub>. This dual behaviour shows that it:
A Is a strong dehydrating agent onlyB Always disproportionates in acid mediumC Is amphoteric exactly like waterD Can act as both oxidant and reductantShow answer & explanation →
Q53.
Deuterium oxide (D<sub>2</sub>O) is preferred over ordinary water as a moderator in nuclear reactors because:
A It slows neutrons while absorbing very fewB It is radioactive and sustains the reactionC It has a far lower boiling point than waterD It strongly absorbs all thermal neutronsShow answer & explanation →
Q54.
Reactions using deuterium generally proceed more slowly than with ordinary hydrogen because:
A Deuterium has a smaller atomic radius than protiumB D–X bonds have lower zero-point energy and break slowerC Deuterium compounds are ionic, not covalentD Deuterium is far more electronegative than protiumShow answer & explanation →
Q55.
In C + H<sub>2</sub>O → CO + H<sub>2</sub> (steam on hot coke), the CO is removed to get pure dihydrogen by:
A Cooling the mixture below CO's boiling pointB Bubbling the gas through concentrated H<sub>2</sub>SO<sub>4</sub>C Shifting CO with steam to CO<sub>2</sub>, then absorbing itD Reacting the mixture directly with nitrogen gasShow answer & explanation →
Q56.
Tritium is used in which applications?
A Nuclear fusion fuel and luminescent markers (radioactive beta emitter)B As a food preservative that extends shelf life through irradiationC As a catalyst that accelerates hydrogenation reactionsD As an industrial solvent for non-polar organic extractionsShow answer & explanation →
Q57.
The kinetic isotope effect (KIE) in chemistry means:
A Reactions with lighter isotopes (H) are faster than with heavier ones (D) because zero-point energy is higher for C-HB All isotopes of a given element react at exactly the identical measured rate under most conditions encountered as frequently observed in practiceC Heavier isotopes such as deuterium consistently react faster than ordinary protium in many documented cases according to conventional understandingD Changing the reaction temperature has little measurable effect on isotope-substituted reactions in routine practiceShow answer & explanation →
Q58.
In the hydrogen economy concept, hydrogen is produced by:
A Electrolysis of water using renewable electricity (green hydrogen)B Direct combustion of fossil fuels to liberate hydrogen gasC Nuclear fission reactions that release hydrogen as a byproductD Microbial fermentation of organic waste materialShow answer & explanation →
Q59.
The anomalous properties of water compared to H<sub>2</sub>S, H<sub>2</sub>Se, H<sub>2</sub>Te are due to:
A Hydrogen bonding in water raises its boiling point far above the trend expected from molecular weightB Water generally having a higher molecular weight than the other hydrides overall in most cases under typical conditionsC Water possessing significant ionic character in its O-H bonds according to standard textbooks in general practiceD Oxygen being a physically larger atom than sulfur, selenium, or tellurium as frequently describedShow answer & explanation →
Q60.
What is the role of palladium in hydrogen technology?
A Pd absorbs up to 900 times its own volume of H<sub>2</sub> (hydrogen storage) and catalyses hydrogenationB Pd functions as a solid-state electrolyte conducting protons in fuel cells in most textbook accountsC Pd forms a passivating oxide layer that prevents hydrogen oxidation largely during normal conditionsD Pd directly converts adsorbed H<sub>2</sub> gas into hydrogen peroxide as generally observed in typical laboratory settingsShow answer & explanation →
Q61.
The Born-Oppenheimer approximation applied to H<sub>2</sub><sup>+</sup> (simplest molecular ion) allows:
A Separation of nuclear and electronic motion to solve the Schrodinger equation exactlyB The simultaneous exact calculation of every molecular property at once under usual circumstancesC Complete neglect of quantum mechanical effects in the system according to most researchersD A mainly classical mechanical treatment of the nuclei and electron in the majority of cases studiedShow answer & explanation →
Q62.
Why does H<sub>2</sub>O<sub>2</sub> have a higher boiling point (150°C) than water (100°C) despite having similar molecular weight?
A Both O atoms in H<sub>2</sub>O<sub>2</sub> form hydrogen bonds (more H-bond donors and acceptors per molecule)B H<sub>2</sub>O<sub>2</sub> carries a significant degree of ionic character unlike water as widely reportedC H<sub>2</sub>O<sub>2</sub> molecules are generally much larger in physical size than water in standard practiceD H<sub>2</sub>O<sub>2</sub> lacks hydrogen bonding largely, relying mainly on dispersion forces under most conditions encounteredShow answer & explanation →
Q63.
What is 'hydrogen embrittlement'?
A Absorption of H<sub>2</sub> into metal lattice weakens metallic bonds, making the metal brittle and prone to crackingB Hydrogen gas chemically reacting with the surface metal oxide layer to release water vapour as frequently observed in practiceC The bulk metal slowly dissolving away when largely immersed in liquid hydrogen peroxide in many documented casesD The thermal softening effect produced by burning hydrogen gas nearby the metal surface according to conventional understandingShow answer & explanation →
Q64.
The para-hydrogen to ortho-hydrogen ratio at very low temperature approaches:
A 100% para-H<sub>2</sub> (para is lower energy at low T)B 100% ortho-H<sub>2</sub>C 50:50D 75:25 ortho:para (room temperature equilibrium)Show answer & explanation →
Q65.
Hydrogen fuel cells generate electricity by:
A Electrochemical oxidation of H<sub>2</sub> at anode, reduction of O<sub>2</sub> at cathode, water as byproductB Direct flame combustion of hydrogen gas inside the cell housing in routine practiceC Controlled nuclear fusion of hydrogen nuclei within the cell overall in most casesD Thermal decomposition of hydrogen peroxide releasing oxygen gas under typical conditionsShow answer & explanation →
Q66.
What is the significance of the 21 cm hydrogen emission line in astronomy?
A Spin-flip transition of electron in hydrogen; used to map galactic structure and detect neutral hydrogen cloudsB A strong ultraviolet absorption line produced by electronic excitation of bound hydrogen according to standard textbooksC An energetic X-ray emission line produced by highly ionised hydrogen plasma in general practice as frequently describedD A mainly theoretical signal that remains permanently undetectable by any telescope in most textbook accountsShow answer & explanation →
Q67.
In which reaction does H<sub>2</sub>O<sub>2</sub> act as an oxidising agent in acidic medium?
A H<sub>2</sub>O<sub>2</sub> + 2Fe<sup>2+</sup> + 2H+ → 2Fe<sup>3+</sup> + 2H<sub>2</sub>OB 2H<sub>2</sub>O<sub>2</sub> → 2H<sub>2</sub>O + O<sub>2</sub> (decomposition)C H<sub>2</sub>O<sub>2</sub> + 2KMnO<sub>4</sub> → productsD H<sub>2</sub>O<sub>2</sub> + Na<sub>2</sub>SO<sub>3</sub> → Na<sub>2</sub>SO<sub>4</sub> + H<sub>2</sub>OShow answer & explanation →
Q68.
Which condition favours formation of ionic hydrides over covalent hydrides?
A Low electronegativity and large size of the metal (strong electropositive character)B An unusually high electronegativity of the metal element forming the hydrideC A particularly small atomic size of the non-metal that hydrogen bonds toD Simply maintaining a high reaction temperature throughout the synthesis processShow answer & explanation →
Q69.
The dielectric constant of heavy water (D<sub>2</sub>O) compared to ordinary water (H<sub>2</sub>O):
A Slightly lower (~78 vs 80) because D<sub>2</sub>O hydrogen bonds are slightly stronger making it less polarisableB Noticeably higher than ordinary water mainly because of its greater molecular mass during normal conditionsC Exactly the same numerical value as ordinary water since both share identical polarity as generally observedD Much lower, falling below 20, supposedly due to unusually weak deuterium bonding in typical laboratory settingsShow answer & explanation →
Q70.
Hydrogen can exist as a metallic solid under extreme pressure. This was first observed in:
A Theoretical prediction; metallic H may exist in gas giant planet cores (Jupiter)B Routine laboratory observation at ordinary atmospheric pressure under usual circumstancesC A stable solid state generally by cooling hydrogen to -200°C according to most researchersD Mainly ever observed as an ordinary cryogenic liquid in the majority of cases studiedShow answer & explanation →
Q71.
The equilibrium 2H<sub>2</sub>O(l) ⇌ H<sub>3</sub>O<sup>+</sup>(aq) + OH-(aq) has Kw = 10-14 at 25°C. At 37°C (body temperature), Kw is:
A Greater than 10-14 (autodissociation is endothermic, favoured by higher T)B Less than 10-14, since higher temperature suppresses autodissociationC Unchanged at exactly 10-14 regardless of temperatureD Effectively zero, since water barely dissociates at body temperatureShow answer & explanation →
Q72.
In terms of bond enthalpy, the reaction H<sub>2</sub> → 2H requires approximately 436 kJ/mol. This means:
A H<sub>2</sub> is thermally stable; significant energy must be supplied to create atomic hydrogenB H<sub>2</sub> is an inherently unstable molecule that decomposes readily at room temperatureC Free hydrogen atoms are more thermodynamically stable than H<sub>2</sub> moleculesD The dissociation reaction proceeds spontaneously without any energy inputShow answer & explanation →
Q73.
Why is water considered a universal solvent?
A High polarity, small size, and ability to hydrogen bond with solutes enables it to dissolve many ionic and polar covalent substancesB Its complete lack of visible colour is what supposedly allows it to dissolve coloured substances so easily as widely reported in standard practiceC Its non-toxic nature toward living cells is supposedly what allows it to dissolve so many different compounds under most conditions encounteredD It happens to have the lowest boiling point of any common liquid solvent used in laboratory chemistry as frequently observed in practiceShow answer & explanation →
Q74.
Proton transfer reactions (Bronsted acid-base) are fast because:
A Protons (H+) are very small and have no electrons, so tunnelling and fast diffusion in water occur via the Grotthuss mechanismB Proton transfer reactions proceed with highly zero activation energy barrier at any temperature in many documented casesC Changing the reaction temperature has little measurable effect on the proton transfer rate according to conventional understandingD Such reactions occur quickly mainly because bulk liquid water happens to be present nearby in routine practice overall in most casesShow answer & explanation →
Q75.
The H–H bond enthalpy (436 kJ/mol) is one of the highest for a single bond, which explains why dihydrogen is:
A highly reactive at room temperatureB relatively inert at room temperatureC a powerful oxidising agent overallD predominantly ionic in characterShow answer & explanation →