1.00g of mixture of calcium carbonate and calcium oxide liberated 0.33g of carbon dioxide on strong heating. The percentage of calcium oxide in the mixture is? (Ca = 40, C = 12, O = 16)

  • A 5
  • B 15
  • C 25
  • D 35
  • E 50
jamb 1982chemistry

The correct answer is C. 25

CaCO3 + CaO \(\to\) 2CaO + 2CO2

44gm of CO3 is liberated by 100gm of CaCO3

0.33gm of CO2 will be liberated by \(\frac{100}{44}\) x 0.33

= 0.75 of CaCO3

Amount of CaO = 1 - 0.75

= 0.25

% of CaO = \(\frac{0.25}{1} \times \frac{100}{1}\)

= 25%

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