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JEE Main 2024 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 9 April 2024, Shift 1, Chemistry Q83

Question 83 of 90 in this shift, Chemistry question 23 of 30, Section B.

The heat of solution of anhydrous

\mathrm{CuSO_4}

and

\mathrm{CuSO_4\cdot5H_2O}

are

-70

kJ mol

^{-1}

and

+12

kJ mol

^{-1}

respectively. The heat of hydration of

\mathrm{CuSO_4}

to

\mathrm{CuSO_4\cdot5H_2O}

is

-x

kJ. The value of

x

is ________. (nearest integer).

Official answer

82

NTA final key.

Chapter: Thermodynamics (Chemistry)
Topic: Enthalpy and Hess's Law
Idea tested: Enthalpy of Solution and Hydration

Same idea in other shifts

Asked 2× in all

7 Apr 2025, Shift 2 · Q53The hydration energies of $\mathrm{K^+}$ and $\mathrm{Cl^-}$ are $-x$ and $-y$ kJ/mol respectively. If lattice energy of KCl is $-z$ …EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.