In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium…

1. Analyze the Question

We are given a neutralization reaction between a base (Sodium hydroxide, NaOH) and an acid (Sulphuric acid, $H_2SO_4$). We need to find the volume of the base required to neutralize a specific volume and concentration of the acid.

2. Explain the Concept

To solve this, we use the titration formula:

Where:

• $C_a$ = Concentration of the acid
• $V_a$ = Volume of the acid
• $n_a$ = Number of moles of acid from the balanced equation
• $C_b$ = Concentration of the base
• $V_b$ = Volume of the base
• $n_b$ = Number of moles of base from the balanced equation

First, we must write the balanced chemical equation:

From the equation:

• $n_a = 1$ (coefficient of $H_2SO_4$)
• $n_b = 2$ (coefficient of $NaOH$)

3. Show the Solution

Given data:

• $C_a = 1.25 \, \text{mol/dm}^3$
• $V_a = 10 \, \text{cm}^3$
• $C_b = 0.5 \, \text{mol/dm}^3$
• $V_b = ?$

Step-by-step calculation: Substitute the values into the formula:

Multiply both sides:

Multiply by 2 to clear the fraction:

Solve for $V_b$:

4. Identify the Answer

The volume of sodium hydroxide required is 50 cm$^3$. This corresponds to option D.

5. Tip

Always remember to balance your chemical equation first! Many students forget the coefficients ($n_a$ and $n_b$), which leads to incorrect answers. In neutralization reactions, the stoichiometry (the ratio of moles) is just as important as the concentration and volume.