Question

When 50. milliliters of an HNO3 solution is

exactly neutralized by 150 milliliters of a 0.50 M
solution of KOH, what is the concentration of
HNO3?
(1) 1.0 M (3) 3.0 M
(2) 1.5 M (4) 0.5 M

Answer 1

The reaction formula is HNO3 + KOH = KNO3 + H2O. The mole number of HNO3 and KOH is the same. So the concentration of HNO3 is 150*0.5/50=1.5 M. So the answer is (2).

Answer 2

Answer : The correct option is, (2) 1.5 M

solution :

According to the neutralization law,

`M_1V_1=M_2V_2`

where,

`M_1` = molarity of
`HNO_3` solution = ?

`V_1` = volume of
`HNO_3` solution = 50 ml

`M_2` = molarity of KOH solution = 0.50 M

`V_2` = volume of KOH solution = 150 ml

Now put all the given values in the above law, we get the volume of
`HNO_3` solution.

`M_1* (50ml)=(0.50M)* (150ml)`

`M_1=1.5M`

Therefore, the concentration of
`HNO_3` is, 1.5 M