Question

Hydrochloric acid solution $A$ and $B$ have a concentration of $0.5N$ and $0.1N$ respectively. The volume of solutions $A$ and $B$ required to make $2$ litres of $0.2NHCl$ are:

• A. $0.5$ L of $A+1.5$ L of $B$
• B. $1.5$ L of $A+0.5$ L of $B$
• C. $1.0$ L of $A+1.0$ L of $B$
• D. $0.75$ L of $A+1.25$ L of $B$

Answer 1

The correct option is A $0.5$ L of $A+1.5$ L of $B$

The normality equation is

$N_1{V}_1+N_2{V}_2=N_3(V_1+V_2)$

Suppose the volume of A mixed is $x$.

Then the volume of B will be $(2-x)$.

Applying normality equation,

$N_1{V}_1+N_2{V}_2=N_3(V_1+V_2)0.5x+0.1(2-x)=0.2\times 20.5x+0.2-0.2x=0.4x=0.5$

So, volume of A will be 0.5 lit

Volume of B will be = $2-0.5$ = 1.5 lit

Hence, the correct option is $A$