Blog Log in Get Started Free

Chemical Thermodynamics MCQs for NEET — Chemistry Questions with Answers

Practice free Chemical Thermodynamics (Chemistry) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.

All Physics Chemistry Botany Zoology

Language English हिंदी

Chapter Difficulty Show only questions I answered incorrectly Clear Register free for difficulty & keyword filters

● ● ● ● ●

In which of the following reactions does the heat change represent the heat of formation of water [EAMCET 1991]

$2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (l); Δ H = - 116 k c a l$

$H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ H = - 58 k c a l$

$H^{+} (a q .) + O H^{-} (a q .) \to 2 H_{2} O (l); Δ H = - 13 .7 k c a l$

$C_{2} H_{2} (g) + 2 \frac{1}{2} O_{2} (g) \to 2 C O_{2} (g) + H_{2} O (l)$ ; $Δ H = - 310 k c a l$

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

Heat of formation is the formation of one mole of the substance from its elements.

● ● ● ● ●

Based on the following thermochemical equations

$H_{2} O (g) + C (s) \to C O (g) + H_{2} (g); Δ H = 131 k J$

$C O (g) + \frac{1}{2} O_{2} (g) \to C O_{2} (g); Δ H = - 282 k J$

$H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (g); Δ H = - 242 k J$

$C (s) + O_{2} (g) \to C O_{2} (g); Δ H = X k J$

The value of X is [CBSE PMT 1992]

–393 kJ

–655 kJ

+393 kJ

+655 kJ

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

eq. (i) + eq. (ii) + eq. (iii) gives

$X = 131 - 282 - 242 = - 393 k J$ .

● ● ● ● ●

If enthalpies of formation of C₂H₄(g), CO₂(g) and H₂O(l) at 25°C and 1 atm pressure be 52, – 394 and –286 kJ mol^–1 respectively, the enthalpy of combustion of C₂H₄(g) will be [CBSE PMT 1995; AIIMS 1998; Pb. PMT 1999]

+1412 kJ mol^–1

–1412 kJ mol^–1

+141.2 kJ mol^–1

–141.2 kJ mol^–1

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$C_{2} H_{4} + 3 O_{2} \to 2 C O_{2} + 2 H_{2} O$

$Δ H_{reaction} = [2 \times Δ H_{f}^{o} (C O_{2}) + 2 \times Δ H_{f}^{o} (H_{2} O)]$ $- [Δ H_{f}^{o} (C_{2} H_{4}) + 3 \times Δ H_{f}^{o} (O_{2})]$

$= [2 (- 394) + 2 (- 286)] - [52 + 0] = - 1412 k J$ .

● ● ● ● ●

Ozone is prepared by passing silent electric discharge through oxygen. In this reaction [AFMC 1998]

Energy is given out

Energy is absorbed

Oxygen is loaded with energy

Oxygen is dissociated into atoms

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$3 O_{2} ⇌ 2 O_{3}$ – energy is given out.

● ● ● ● ●

Combustion of glucose takes place according to the equation, $C_{6} H_{12} O_{6} + 6 O_{2} \to 6 C O_{2} + 6 H_{2} O$ , $Δ H = - 72 k c a l$ . How much energy will be required for the production of 1.6 g of glucose (Molecular mass of glucose = 180 g) [AFMC 1999]

0.064 kcal

0.64 kcal

6.4 kcal

64 kcal

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$Δ H p e r 1 .6 g = \frac{72 \times 1 .6}{180} = 0 .64 k c a l$ .

● ● ● ● ●

Which of the following compounds will absorb the maximum quantity of heat when dissolved in the same amount of water ? The heats of solution of these compounds at 25°C in kJ/mole of each solute is given in brackets [AMU (Engg.) 2000]

$H N O_{3} (Δ H = - 33)$

$K C l (Δ H = + 17 .64)$

$N H_{4} N O_{3} (Δ H = + 25 .5)$

$H C l (Δ H = - 74 .1)$

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

More +ve is ΔH_s more is heat of solution.

● ● ● ● ●

A system is changed from state A to state B by one path and from B to A another path. If E₁ and E₂ are the corresponding changes in internal energy, then [Pb. PMT 2001]

$E_{1} + E_{2} = - v e$

$E_{1} + E_{2} = + v e$

$E_{1} + E_{2} = 0$

None of these

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

ΔE = 0 for a cyclic process.

● ● ● ● ●

If (i) $C + O_{2} \to C O_{2}$ , (ii) $C + 1 / 2 O_{2} \to C O$ , (iii) $C O + 1 / 2 O_{2} \to C O_{2}$ , the heats of reaction are Q, –12, –10 respectively. Then Q = [Orissa JEE 2004]

– 2

– 22

– 16

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

$C + O_{2} \to C O_{2}$ ; ΔH = q

$C + 1 / 2 O_{2} \to C O$ ; ΔH = –12 …..(i)

$C O + 1 / 2 O_{2} \to C O_{2}$ ; ΔH = –10 …..(ii)

adding equation (i) and (ii) we can get

ΔH = –12 + (–10) = –22

● ● ● ● ●

Adsorption of gases on solid surface is generally exothermic because [IIT JEE (Screening) 2004]

Enthalpy is positive

Entropy decreases

Entropy increases

Free energy increase

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

Due to randomness of particles is reduced since entropy decreases.

● ● ● ● ●

Two mole of an ideal gas is expanded isothermally and reversibly from 1 litre ot 10 litre at 300 K. The enthalpy change (in kJ) for the process is [IIT JEE (Screening) 2004]

11.4 kJ

–11.4 kJ

0 kJ

4.8 kJ

You've reached today's free limit of 20 questions. Log in to keep practising for free.

Explanation

ΔH = nCp ΔT

The process is isothermal therefore

ΔG = 0; ∴ ΔH = 0

Ready to ace NEET?

Free access · No credit card required

Browse All Questions Create Free Account

Frequently Asked Questions

Yes. You can attempt every Chemical Thermodynamics question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.

No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.

The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.