Some Basic Concepts of Chemistry - Result Question 13

18. The molarity of a solution obtained by mixing 750 mL of 0.5 M HCl with 250 mL of 2 M HCl will be

(2013 Main)

(a) 0.875 M

(b) 1.00 M

(c) 1.75 M

(d) 0.0975 M

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Answer:

Correct Answer: 18. (a)

Solution:

  1. From the formula, $M_f=\frac{M_1 V_1+M_2 V_2}{V_1+V_2}$

Given,

$\begin{aligned} V_1 & =750 \mathrm{~mL}, M_1=0.5 \mathrm{M} \\ V_2 & =250 \mathrm{~mL}, M_2=2 \mathrm{M} \\ & =\frac{750 \times 0.5+250 \times 2}{750+250}=\frac{875}{1000}=0.875 \mathrm{M} \end{aligned}$