When the same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide, the ratio of volume of hydrogen evolved is :

Options

A. `50mL`
B. `25mL`
C. `20mL`
D. `10mL`

Answer

2

Explanation

Let VmL of NaOH be needed to give `CH_(3)COONa`
`{:(NaOH,+,CH_(3)COOH,rarr,CH_(3)COONa,+,H_(2)O),(0.2xxV,,50xx0.2,,0,,0),(-,,[10-0.2V],,0.2V,,0.2V):}`
`:. " "pH=pK_(a)+log.(["Salt"])/(["Acid"])=pK_(a)-pK_(a)+log.(["Salt"])/([Aci d])=14-9.26+log.(["Salt"])/(["Acid"])`
`=14-9.26+log.([(0.2V)/(50+V)])/([(0-0.2V)/(50+V)])`
`4.74=4.74+log.[(0.2V)/(10-0.2V)]" ":." "V=(10)/(0.4)=25mL`