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

`0.75\ \text{M}`

Step-by-step 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=(V_2C_2)/(V_1)\\\Rightarrow C_1=(15* 1)/(20)\\\Rightarrow C_1=0.75\ \text{M}`

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