$5 \mathrm{~L}$ of $1 \mathrm{M} \mathrm{NaOH}$ solution is mixed with $3 \mathrm{~L}$ of $0.5 \mathrm{M} \mathrm{NaOH}$ solution. Find out the molarity of the resultant solution:

Question

Aicharya · Accepted Answer

2.5 L $1 \mathrm{M}$ Naoh with 3 L $0.5 \mathrm{M}$ $\mathrm{NaOH}$.
Intially, Number of moles in $2.5 \mathrm{~L}$,
$\begin{aligned}
1 \mathrm{M} \mathrm{NaOH} & =2.5 \times 1 \\
& =2.5 \text { moles }
\end{aligned}$
Number of moles in $3 \mathrm{~L}, 0.5 \mathrm{M} \mathrm{NaOH}$ $=3 \times 0.5=1.5$ moles.
$\Rightarrow$ Total number of moles in final mixture $=2.5+1.5=4.0$ moles .
The total volume of solution $=2.5+3=5.5 \mathrm{~L}$
$\begin{aligned}
& \Rightarrow \text { Molarity of final solution }=\frac{4}{5.5} \\
& =0.728 \mathrm{M}
\end{aligned}$

$5 \mathrm{~L}$ of $1 \mathrm{M} \mathrm{NaOH}$ solution is mixed with $3 \mathrm{~L}$ of $0.5 \mathrm{M}…

Solution