gatemastery.com

GATE Chemical Daily Practice

One well-chosen question every day can do more for your GATE score than hours of random study.
This page is designed to help you practice consistently, focus on exam-relevant numericals, and strengthen concepts that GATE repeatedly tests.

How to Use This Page?

  1. Attempt the question on your own (10–15 minutes).
  2. Write down assumptions and formulas before checking the solution.
  3. Compare your approach with the explained solution.
  4. Note the concept or mistake — and move on.
  5. Consistency matters more than volume.

Questions here are selected based on previous year trends and common conceptual traps in GATE Chemical Engineering.

👉 Today’s Question

GATE Chemical – Daily Practice (PYQs)

Question 1 (Thermodynamics)

An ideal gas undergoes an isothermal, reversible expansion from volume V1 to V2 at temperature T. What is the work done by the gas?

  • A. RT ln(V1/V2)
  • B. RT ln(V2/V1)
  • C. P(V2 − V1)
  • D. Zero

Correct Answer: B

Explanation:
For an isothermal, reversible process involving an ideal gas:

W = ∫ P dV

Using the ideal gas equation:

P = RT / V

Substituting:

W = RT ∫ (dV / V)

W = RT ln(V2/V1)

Common mistake: Reversing the volume ratio inside the logarithm.

Question 2 (Process Calculations)

A gas mixture contains 30 mol% nitrogen and 70 mol% hydrogen. What is the average molecular weight of the mixture?

Given:
N2 = 28
H2 = 2

Correct Answer: 10.4

Explanation:
The average molecular weight of a gas mixture is calculated using mole fractions:

M̄ = Σ(yiMi)

= (0.30 × 28) + (0.70 × 2)

= 8.4 + 1.4 = 10.4

Common mistake: Using mass fraction instead of mole fraction.

Question 3 (Fluid Mechanics)

The Reynolds number for flow through a circular pipe is 1500. Identify the nature of flow.

  • A. Turbulent
  • B. Transitional
  • C. Laminar
  • D. Fully developed turbulent

Correct Answer: C

Explanation:
For flow in a circular pipe:

Re < 2100 → Laminar flow

2100 < Re < 4000 → Transitional flow

Re > 4000 → Turbulent flow

Since Re = 1500, which is less than 2100, the flow is laminar.

Common mistake: Confusing laminar and transitional limits.

‎ ‎ 
‎    Advertisement ‎ 
‎ ‎  ‎ ‎  ‎ ‎

GATE Chemical – Daily Practice

Today’s Questions

Question 1 · Thermodynamics

An ideal gas undergoes an isothermal and reversible expansion from volume V1 to V2 at a constant temperature T. Which of the following expressions represents the work done by the gas?

  • A. RT ln(V1/V2)
  • B. RT ln(V2/V1)
  • C. P(V2 − V1)
  • D. Zero

Answer: B

For an isothermal reversible process, pressure varies inversely with volume. Integrating P = RT / V with respect to V gives W = RT ln(V2/V1).

Question 2 · Process Calculations

A gas mixture contains 30 mol% nitrogen and 70 mol% hydrogen. The molecular weights of N2 and H2 are 28 and 2 respectively. Determine the average molecular weight of the mixture.

Answer: 10.4

Average molecular weight is calculated using mole fractions. Multiplying each component’s mole fraction with its molecular weight and summing the values gives the final result.

Question 3 · Fluid Mechanics

The Reynolds number for flow of a fluid through a circular pipe is 1500. Identify the nature of the flow.

  • A. Turbulent
  • B. Transitional
  • C. Laminar
  • D. Fully developed turbulent

Answer: C

For pipe flow, Reynolds number less than 2100 corresponds to laminar flow. Since the given value is 1500, the flow remains laminar.