Question

Raghav was performing an experiment. He observed that 2 gm of lead nitrate decomposes to form 2 gm of lead oxide. Find the mass of lead oxide formed by the decomposition of 500 gm of lead nitrate if only 80% of lead nitrate is pure.

• A. 289.56 gm
• B. 272.35 gm
• C. 269.55 gm
• D. 312.4 gm

Answer 1

The correct option is C

269.55 gm

$2Pb(N{O}_3{)}_2\to 2PbO+4N{O}_2+O_2$
$(207.2+(14.0067+15.99\times 3)\times 2)(207.2+15.99)$
=331.2 gm
=223.19 gm
Since only 80% lead nitrate is pure
So, $\frac{80}{100}\times 500$
=400 gm
Since, 331.2 gm of lead nitrate forms 223.19 gm lead oxide
Therefore 400 gm of lead nitrate forms $\frac{400\times 223.19}{331.2}$
=269.55 g