Question

Upon fully dissolving a 2g metal in sulphuric acid

Answer 1

Step 1:

Equivalent mass of SO2−4 radical =IonicmassValency

=962

=48

Mass of metal sulphate=4.51g

Mass of metal=2.0g

Mass of sulphate metal =4.51-2.0=2.51g

2.51g of sulphate combine with 2.0g of metal

So,48g of sulphate will combine with =22.51×48

⇒38.24g metal

Equivalent mass of metal=38.24

Step 2:

According to Dulong and Petit's law

Approximate atomic mass=6.4specificheat

=6.40.057

=112.5

Valency =(Approx)atomicmassEquivalentmass

=112.538.24

=2.9

=3(approx)

Step 3:

∴ Exact atomic mass=38.24×3

⇒114.72

Hence (b) is the correct answer.