Objective question (single correct answer).
i. `H_(3) PO_(4)` is a tribasic acid and one of its salt is `NaH_(2) PO_(4)`. What volume of `1M NaOH` solution should be added to `12 g` of `NaH_(2) PO_(4)` to convert in into `Na_(3) PO_(4)` ?
ii. The normality of a mixture obtained mixing `100 mL` of `0.2 m H_(2) SO_(4)` with `100 mL` of `0.2 M NaOH` is:
a. `0.05 N` b. `0.1 N` c. `0.15 N` d. `0.2 N`
iii. `100 mL` solution of `0.1 N HCl` was titrated with `0.2 N` `NaOH` solutions. The titration was discontinued after adding `30 mL` of `NaOH` solution. The reamining titration was completed by adding `0.25 N KOH` solution. The volume of `KOH` required from completing the titration is:
a. `70 mL` b. `35 mL` c. `32 mL` d. `16 mL`

Options

A. 100 cc
B. 300 cc
C. 200 cc
D. 80 cc

Answer

C

Explanation

meq of `"NaOH = meq of "NaH_(2)PO_(4)`
Volume of 1M NaOH that must be added `=(12xx2xx1000)/(120)="200 cc"`