The degree of dissociation of 0.1 M weak acid HA is 0.5%. If 2 mL of 1.0MHA solution is diluted to 32 mL the degree of dissociation of acid and `H_(3)O^(+)` ion concentration in the resulting solution will be respectively

Options

A. `0.02and3.125xx10^(-4)`
B. `1.25xx10^(-3)and0.02`
C. `6.02and1.25xx10^(-3)`
D. `0.02and8.0xx10^(-12)`

Answer

C

Explanation

`alpha_(1)=0.005=sqrt(K_(a)xxC_(1))`
Molarity of diluted solution `2xx1=32xxM,M=1//16(C_(2))`
`alpha_(2)=sqrt((K_(a))/(C_(2)))=0.005sqrt(16)=0.02`
`H_(3)O^(+)=C_(2)alpha_(2)=(0.02)/(16)=1.25xx10^(-3)M`