Skip to content
GK24
Prime
General ScienceHardAsked in: NDA · NDA-II 2026, GAT

Consider the following statements regarding the properties of hydrogen and water : I. Tritium, the isotope of hydrogen, is radioactive and emits low energy alpha particles. II. In the gas phase, the structure of water is linear. III. The basic principle of a hydrogen economy is the transportation and storage of energy in the form of liquid or gaseous molecular hydrogen. Which of the statements given above is/are not correct?

  1. A.I and II only
  2. B.II and III only
  3. C.I and III only
  4. D.II only

Correct answer

A. I and II only

Explanation

The correct answer is A, I and II only. Tritium gives out beta particles, not alpha particles, and a water molecule is bent, not linear, so these two statements are wrong.

Tritium (hydrogen-3) has one proton and two neutrons. It is radioactive with a half-life of about 12.3 years and decays by emitting low-energy beta particles (electrons), turning into helium-3. A water molecule has two lone pairs on oxygen that push the two O–H bonds together, giving a bent (V-shaped) structure with a bond angle of about 104.5°, in the gas phase as well. The idea of a hydrogen economy is to store and carry energy as liquid or gaseous hydrogen, so statement III is correct.

B is wrong because statement III is correct and statement I is not.

C is wrong because statement III is correct, while statement II is not.

D is wrong because statement I is also incorrect.

Exam tip: tritium is the only radioactive hydrogen isotope and is a beta emitter; water is bent at about 104.5°.

Practice Questions

View all
Q1.General ScienceAsked in: UPSC Civil Services · CSE Prelims 2022, GS Paper IMedium

Which of the following are nitrogen-fixing plants?

1. Alfalfa

2. Amaranth

3. Chickpea

4. Clover

5. Purslane (Kulfa)

6. Spinach

Select the correct answer using the code given below:

  1. A.1, 3 and 4 only
  2. B.1, 3, 5 and 6 only
  3. C.2, 4, 5 and 6 only
  4. D.1, 2, 4, 5 and 6
Show answer
Correct answer: A. 1, 3 and 4 only

Alfalfa, chickpea and clover are legumes, and legumes fix nitrogen. Plants of the legume family (Fabaceae) carry root nodules that house Rhizobium bacteria.

Q2.General ScienceAsked in: UPSC CAPF · CAPF 2017, Paper IMedium

The mass number of an element is NOT changed when it emits

  1. A.Alpha and Beta radiations only
  2. B.Alpha and Gamma radiations only
  3. C.Beta and Gamma radiations only
  4. D.Alpha, Beta and Gamma radiations
Show answer
Correct answer: C. Beta and Gamma radiations only

Neither beta nor gamma emission changes the total number of protons and neutrons in a nucleus, so the mass number stays the same.

Q3.General ScienceAsked in: UPSC CAPF · CAPF 2025, Paper IMedium

Which one among the following statements about facilitated transport in plants is correct?

  1. A.All passive transports are types of facilitated transport.
  2. B.Facilitated transport is an example of active transport.
  3. C.Water moves across plasma membrane by active transport.
  4. D.Facilitated transport requires assistance of carrier proteins.
Show answer
Correct answer: D. Facilitated transport requires assistance of carrier proteins.

In facilitated transport, molecules cross the membrane with the help of membrane proteins, while still moving down their concentration gradient.

Q4.General ScienceAsked in: UPSC CAPF · CAPF 2017, Paper IMedium

Who among the following has coined the term 'Quark', the fundamental particles that make up protons and neutrons in an atomic nucleus ?

  1. A.Richard Feynman
  2. B.Murray Gell-Mann
  3. C.Albert Einstein
  4. D.Niels Bohr
Show answer
Correct answer: B. Murray Gell-Mann

The American physicist Murray Gell-Mann proposed quarks in 1964 and gave them their name. Gell-Mann, and independently George Zweig, suggested that protons, neutrons and other such particles are built from smaller units.