Question

what is the concentration of an aqueous solution containing 2.58 g of nh4cl in 25.5 ml of solution? the molar mass of nh4cl is 53.5 g/mol.

o 0.185 m
o 1.23 m
o 1.89 m
o 5.41 m
o 0.813 m

Explanation:

Step1: Calculate moles of NH₄Cl

Use formula $n=\frac{m}{M}$, where $m = 2.58\ g$ and $M=53.5\ g/mol$. So $n=\frac{2.58}{53.5}\ mol$.
$n = 0.0482\ mol$

Step2: Convert volume to liters

Given volume $V = 25.5\ mL$. Since $1\ L=1000\ mL$, then $V=25.5\div1000 = 0.0255\ L$.

Step3: Calculate molarity

Use formula $M=\frac{n}{V}$, where $n = 0.0482\ mol$ and $V = 0.0255\ L$. So $M=\frac{0.0482}{0.0255}\ M$.
$M = 1.89\ M$

Answer:

1.89 M