An impure sample of pyrolusite ore (.MnO2.) consist of 70 %MnO2, 20 % inert impurities and rest is the moisture. On strong heating, all MnO2 is converted into MnO along with formation of O2 . What is the % of Mn in dried sample? (Atomic mass of Mn = 55)

Question

An impure sample of pyrolusite ore (.MnO2.) consist of 70 %MnO2, 20 % inert impurities and rest is the moisture. On strong heating, all MnO2 is converted into MnO along with formation of O2 . What is the % of Mn in dried sample? (Atomic mass of Mn = 55) (A) 57.4 % (B) 50 % (C) 47.8 % (D) 70.1 %

Tardigrade Admin · Accepted Answer

underset(70/87)MnO2 arrow underset(70/87)MnO + (1/2) O2 % mass of Mn =(((70/87)) 55 × 100/((70)87) 71 + 20)=(44 .25/57 + 20)× 100=57.4 %

Q. An impure sample of pyrolusite ore $(M n O_{2})$ consist of $70% M n O_{2}, 20%$ inert impurities and rest is the moisture. On strong heating, all $M n O_{2}$ is converted into $M n O$ along with formation of $O_{2}$ . What is the $%$ of $M n$ in dried sample? (Atomic mass of $M n = 55)$

$57.4%$

$50%$

$47.8%$

$70.1%$

$\frac{70}{87} M n O_{2} \to \frac{70}{87} M n O + \frac{1}{2} O_{2}$
% mass of $M n = \frac{( \frac{70}{87} ) 55 \times 100}{( \frac{70}{87} ) 71 + 20} = \frac{44.25}{57 + 20} \times 100 = 57.4%$

Q. An impure sample of pyrolusite ore (MnO2​) consist of 70%MnO2​,20% inert impurities and rest is the moisture. On strong heating, all MnO2​ is converted into MnO along with formation of O2​ . What is the % of Mn in dried sample? (Atomic mass of Mn=55)

57.4%

50%

47.8%

70.1%