Hydrogen JEE Main PYQs (2020–2023)

Solved Hydrogen PYQs

3 recent questions with answers. The full set of 60 is free to practise.

1. JEE Main 2023EasyPosition, Isotopes and Preparation of Dihydrogen
   Q1

   Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.
   
   Assertion A : Isotopes of hydrogen have almost same chemical properties, but difference in their rates of reaction.
   
   Reason R : Isotopes of hydrogen have different enthalpy of bond dissociation.
   
   In the light of the above statements, choose the most appropriate answer from the options given below:

   • AA is not correct but R is correct
   • BBoth A and R are correct but R is NOT the correct explanation of A
   • CA is correct but R is not correct
   • DBoth A and R are correct and R is the correct explanation of A

   Show answer & solution

   Correct answer: (D)

   Assertion A : Isotopes of hydrogen (protium, deuterium, and tritium) have almost the same chemical properties because they have the same number of protons and electrons, which dictate chemical behavior. However, they differ in their rates of reaction due to differences in their atomic masses, which affect reaction kinetics.
   
   Reason R : The isotopes of hydrogen have different enthalpy of bond dissociation due to their differences in atomic mass. The stronger bond in deuterium compared to protium, for example, leads to higher bond dissociation enthalpy. This, in turn, influences the rate of reactions involving these isotopes, as breaking the bonds requires different amounts of energy.
   
   , the correct answer is Both A and R are correct, and R is the correct explanation of A.
2. JEE Main 2023MediumHard and Soft Water & Softening Methods
   Q2

   Given below are two statements :
   
   Statement I : Permutit process is more efficient compared to the synthetic resin method for the softening of water.
   
   Statement II : Synthetic resin method results in the formation of soluble sodium salts.
   
   In the light of the above statements, choose the most appropriate answer from the options given below:

   • AStatement I is correct but Statement II is incorrect
   • BBoth the Statements I and II are correct
   • CBoth the Statements I and II are incorrect
   • DStatement I is incorrect but Statement II is correct

   Show answer & solution

   Correct answer: (C)

   I. Synthetic resin is more efficient as cations as well as anions responsible for removal of permanent hardness.
   
   . In synthetic resin method, cations and anions are removed in the form of ppt.
   
   , both statements are incorrect.
3. JEE Main 2023MediumHydrides (Ionic, Covalent, Interstitial)
   Q3

   Which hydride among the following is less stable?

   • ANH ${}_3$
   • BHF
   • CLiH
   • DBeH ${}_2$

   Show answer & solution

   Correct answer: (D)

   The stability of hydrides depends on their bonding and the electronegativity difference between the elements. The greater the electronegativity difference, the more stable the hydride. Based on this, the order of stability of the given hydrides is:
   
   HF > NH ${}_3$ > LiH > BeH ${}_2$
   
   Therefore, the less stable hydride among the given options is BeH ${}_2$ .

Topic-wise question count

Where JEE Main has asked from Hydrogen, most frequent first.

• Hydrogen Peroxide (H2O2): Preparation, Properties & Structure22
• Position, Isotopes and Preparation of Dihydrogen12
• Hard and Soft Water & Softening Methods8
• Heavy Water (D2O) and Hydrogen Economy6
• Water: Structure, Physical & Chemical Properties5
• Properties and Reactions of Dihydrogen5
• Hydrides (Ionic, Covalent, Interstitial)2

Year-wise Hydrogen questions in JEE Main

Number of questions from this chapter in each year's paper(s).