Question

The density of a monobasic strong acid (Molar mass $242 \,g$ mol) is $121 \,kg \,L$ The volume of its solution required for the complete neutralization of $25 \,mL$ of $024\, M\, NaOH$ is ___$\times 10^{-2} mL$ (Nearest integer)

Answer 1

Correct Answer: 12

1. Calculate millimoles of NaOH: 
\[ \text{Millimoles of NaOH} = 0.24 \times 25 = 6 \, \text{mmol}. \] 
2. Since the acid is monobasic, millimoles of acid required = millimoles of NaOH = 6 mmol. 
3. Mass of acid required: 
\[ \text{Mass of acid} = 6 \times 24.2 = 145.2 \, \text{mg}. \] 
4. Volume of acid solution: 
Using \(\text{Volume} = \frac{\text{mass}}{\text{density}}\), 
\[ V = \frac{145.2}{1.21 \times 10^3} = 0.12 \, \text{mL}. \] 
5. Convert to \(10^{-3}\): 
\[ V = 12 \times 10^{-3} \, \text{mL}. \] 
Thus, the volume required is 12 \(\times\) \(10^{-3} mL\). 
Neutralization of a monobasic acid requires equal millimoles of acid and base. Use the density of the acid solution to calculate the required volume.