What volume of hydrogen at N.T.P would be liberated by the action of 50 mL of dilute `H_(2)SO_(4)` of 40 % purity and having a specific gravity of `1.3 g mL^(-1)` on 65 g of zinc ? (Atomic mass of Zn = 65).

Explanation

Step I. Calculation of mass of pure `H_(2)SO_(4)`
Mass of 50 mL of dilute `H_(2)SO_(4)` = Volume `xx` Specific gravity
`= 50 mL xx (1.3 "g mL"^(-1))=65` g
100 g of `H_(2)SO_(4)` solution contain pure acid = 40 g
65 g of `H_(2)SO_(4)` solution contain pure acid `= (40)/(100) xx 65 g = 26 g`.
Step II. Calculate of volume of hydrogen evolved at N.T.P
The reaction involved is :
`{:("Zn"+,H_(2)SO_(4),rarr,ZnSO_(4)+,H_(2)),(65g,2xx1+32+4xx16,,,22.4 L),(,=98g,,,"at N.T.P."):}`
98 g of `H_(2)SO_(4)` evolve `H_(2)` at N.T.P. = 22.4 L
26 g of `H_(2)SO_(4)` evolve `H_(2)` at N.T.P `= (22.4)/(98) xx 26g = 5.94 L`.