Question

What is the concentration in molL-1 of 20 mL of Na2CO3 solution that neutralises 15 mL of 1 M HCl solution?

Answer 1

Answer:

$0.75\ \text{M}$

Explanation:

$C_1$ = Concentration of $Na_2CO_3$

$C_2$ = Concentration of $HCl$ = 1 M

$V_1$ = Volume of $Na_2CO_3$ = 20 mL

$V_2$ = Volume of $HCl$ = 15 mL

We have the relation

$V_1C_1=V_2C_2\\\Rightarrow C_1=\dfrac{V_2C_2}{V_1}\\\Rightarrow C_1=\dfrac{15\times 1}{20}\\\Rightarrow C_1=0.75\ \text{M}$

The concentration of $Na_2CO_3$ is $0.75\ \text{M}$.