Question

The mass of lime obtained by heating 200g of 95% pure limestone is .

• A. 100 g
• B. 108.3 g
• C. 106.4 g
• D. 110.3 g

Answer 1

The correct option is C 106.4 g

Limestone is $CaC{O}_3$(Molecular weight = 100u)

95% pure sample of 200g has $(\frac{95}{100}\times 200)$ = 190g of $CaC{O}_3$.

$CaC{O}_3$$\stackrel{\Delta }{\to }$ $CaO+C{O}_2$
(limestone) (lime)

100 g 56 g

$\therefore$ $100g$ of $CaC{O}_3$ will yield 56g of lime

$\therefore$ 190g of $CaC{O}_3$ will yield $\left(\frac{190\times 56}{100}\right)$ = $106.4g$ of $CaO$