A compound contains $40.0%$ C, $6.67%$ H and $53.33%$ O by mass (C = 12, H = 1, O = 16). Its empirical formula is:

Answer: B

Moles in 100 g: C

= 3.33

, H

= 6.67

, O

= 3.33

. Dividing by the smallest gives

1 : 2.0 : 1

, so the empirical formula is

CH X_{2} O

The mass percentage of nitrogen in urea, CO(NH2)2, is (H = 1, C = 12, N = 14, O = 16): NEET level
A hydrocarbon has empirical formula CH and molar mass 78 g mol^-1 (C = 12, H = 1). Its molecular formula is: NEET level
The mass percentage of water of crystallisation in CuSO4.5H2O is (Cu = 63.5, S = 32, O = 16, H = 1): NEET level
Complete combustion of 0.74 g of an organic compound containing C, H and O gives 1.76 g of CO2 and 0.90 g of H2O (C = 12, H = 1, O = 16). Th... JEE Main level
On strong heating, 28.6 g of washing soda, Na2CO3.xH2O, leaves a residue of 10.6 g of anhydrous Na2CO3 (Na = 23, C = 12, O = 16, H = 1). The... JEE Main level
An oxide of a metal M (atomic mass 56) contains 70% M by mass (O = 16). The formula of the oxide is: JEE Main level