Question

The pH of HCl and \(\text{H}_{2}\text{SO}_{4}\) is same at same temperature. What is the ratio of molar concentration of HCl to \(\text{H}_{2}\text{SO}_{4}\)?

• A. \(1:1\)
• B. \(1:2\)
• C. \(2:1\)
• D. \(1:4\)

Hint:

Equal pH means equal hydrogen ion concentration; HCl gives one H+ per molecule and H2SO4 gives two.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
Equal pH means the hydrogen ion concentration is the same in both solutions.

Step 2: Ions from each acid
HCl gives one \(\text{H}^{+}\): \([\text{H}^{+}] = c_1\).
\(\text{H}_2\text{SO}_4\), taken as fully ionised, gives two: \([\text{H}^{+}] = 2c_2\).

Step 3: Ratio
\(c_1 = 2c_2\), so \(c_1 : c_2 = 2 : 1\).

Final Answer:
The ratio of HCl to H2SO4 concentration is 2:1. \[ \boxed{\text{(C) }2:1} \]