Question 1

White hydrogen is a finite fossil fuel that takes millions of years to form, similar to coal or petroleum.

Accepted Answer

White hydrogen is continuously generated in the Earth's crust through ongoing geological processes like serpentinization and radiolysis, acting more like a continuously replenishing renewable resource.

Question 2

Hydrogen is strictly color-coded by the physical appearance of the gas.

Accepted Answer

The 'colors' of hydrogen (white, green, blue, grey) refer exclusively to its production method or source, not the actual color of the invisible gas. White means naturally occurring.

Question 3

Consider the following statements regarding Natural (White) Hydrogen and its recent discovery in India:
1. It is primarily generated through the process of serpentinization, which involves the reaction of water with iron-rich ultramafic rocks.
2. India's first white hydrogen reserves were discovered by the GSI in the sedimentary limestone basins of the Vindhyan range.
3. Unlike green hydrogen, white hydrogen does not require energy-intensive water electrolysis for its production.
How many of the above statements are correct?

Accepted Answer

(b) Only two — Statement 1 is correct: Serpentinization is a primary geological mechanism for natural hydrogen generation. Statement 2 is incorrect: The first discovery was made in the serpentinized pillow basalts of the Andaman Ophiolite complex (South Andaman), not Vindhyan limestone. Statement 3 is correct: White hydrogen naturally occurs as a gas in geological formations, completely bypassing the need for artificial electrolysis. Therefore, exactly two statements are correct.

Question 4

Match the following hydrogen 'color' nomenclatures with their respective production methods:
List I (Hydrogen Type)
A. Green Hydrogen
B. Blue Hydrogen
C. Grey Hydrogen
D. White Hydrogen

List II (Production Source/Method)
1. Steam Methane Reforming without carbon capture
2. Geologically occurring in underground formations
3. Electrolysis of water using renewable energy
4. Natural gas reforming with Carbon Capture and Storage (CCS)

Select the correct code:

Accepted Answer

(a) A-3, B-4, C-1, D-2 — Green hydrogen (A) is produced via electrolysis using renewable energy (3). Blue hydrogen (B) uses natural gas but captures the emitted carbon (4). Grey hydrogen (C) uses natural gas without capturing carbon (1). White hydrogen (D) is found naturally in geologic formations (2). Option (a) is the only correct matching.

Question 5

Assertion (A): The Andaman and Nicobar Islands are highly prospective for white hydrogen exploration.
Reason (R): The region contains obducted fragments of ancient oceanic crust and upper mantle known as ophiolites, which host ultramafic rocks capable of ongoing serpentinization.
Select the correct answer from the codes below:

Accepted Answer

(a) Both A and R are true and R is the correct explanation of A. — The Andaman Islands host the Andaman Ophiolite suite, which consists of oceanic crust rocks (pillow basalts, peridotites) that were tectonically pushed onto the continental margin. The iron and magnesium-rich (ultramafic) minerals in these rocks react with water in a process called serpentinization, continuously producing natural (white) hydrogen gas. Thus, R provides the exact geological mechanism explaining why A is true.

GSI Discovers Natural Hydrogen Reserves in Andaman

Release of Henley Passport Index July 2025