Question

1gm of a metal was dissolved in 25ml of 2N (f=1.01) sulphuric acid. The excess of acid required 15.1cc of 1N (f=0.8) sodium hydroxide for complete neutralization. Calculate the equivalent weight of the metal.

Answer 1

Answer:

Total HCl⇒25×1=25 mEq

Excess HCl⇒5×1=5 mEq

HCl used ⇒25−5=20 mEq

∴ mEq of HCl = mEq of carbonate

100020Eq=EwWeight of carbonate =Ew1

∴Ew=201000=50

Answer 2

Answer:

Weight of metal =1 gram

Equivalent Weight =?

For this ,

Acid Taken = 25*22*1.01 ml N =  50.5 ml N

For excess acid = 15.1*1*0.8 ml N NaOH = 12.08 ml N NaOH

Acid Left Unused = 12.08 ml N H2SO4

Acid Used =50.5 - 12.08 = 38.42 ml N H2SO4

38.42 ml N H2SO4 neutralises 1 gram metal

1000 ml N H2SO4 neutralises ( 1/38.42 ) * 1000 gram metal = 26.02 gram

So,

Equivalent weight of metal is 26.02 gram .

Explanation: