Question 71:

Read the following statements carefully:

(A) Ultracentrifugation separates molecules based on their density
(B) Gel electrophoresis separates molecules based on their mobility in an electric field
(C) Gel filtration separates molecules based on their size
(D) NMR separates molecules based on their proton signal

Choose the correct answer from the options given below:

(A) (A), (B) and (D) only
(B) (A), (B) and (C) only
(C) (A), (B), (C) and (D)
(D) (B), (C) and (D) only

pH 0 is the lowest value among the options, as the pH scale is logarithmic and decreases with increasing acidity.

Option Analysis

(A) 0: Correct lowest value. pH = -log[H⁺], so pH 0 equals [H⁺] = 1 M (most acidic listed). Lower numbers mean stronger acids.​

(B) 1: Higher than 0. [H⁺] = 0.1 M, 10x less acidic than pH 0.​

(C) 2: Even higher. [H⁺] = 0.01 M, 100x less acidic than pH 0.​

(D) 7: Highest (neutral). [H⁺] = 10⁻⁷ M, pure water level.​

pH Scale Fundamentals

Lowest pH value signals highest acidity on the 0-14 scale used in biology and chemistry. pH 0 tops acidity among common exam options.​

Logarithmic Nature

Each pH unit drop multiplies [H⁺] by 10:

• pH 0: Pure strong acid.

• pH 1-2: Weaker dilutions.​

GATE Relevance

Tests basic scale logic for Life Sciences. Memorize: 0 < 1 < 2 < 7 numerically and acid strength inversely.​