Question

0.92 g of an organic compound containing carbon, hydrogen and oxygen was analysed by combustion method. The increase in mass of the U-tube and the potash bulbs at the end of the operation was found to be 1.08 g and 1.76 g, respectively. Determine the percentage composition of the compound. 

Solution

Correct option is

C = 52.17%; H = 13.04%, O = 34.79%.

 

Increase in mass of U-tube = 1.08 g  

Mass of water formed = 1.08 g 

Since, 18 g of water contain hydrogen = 2 g

1.08 g of water contain hydrogen   

Mass of compound taken for analysis = 0.92 g 

Percentage of hydrogen 

Increase in mass of potash bulbs = 1.76 g 

Mass of carbon dioxide formed = 1.76 g 

Since, 44 g of carbon dioxide contain carbon = 12 g   

1.76 g of carbon dioxide contain carbon   

Percentage of carbon 

                                    = 52.17. 

Percentage of oxygen = 100 – (per cent of C + per cent of H) 

                                    = 100 – (52.17 + 13.04) 

                                    = 100 – 65.21  

                                    = 34.79 

Composition of the compound : C = 52.17%; H = 13.04%, O = 34.79%.

SIMILAR QUESTIONS

Q1

An organic substance (0.2115 g) on complete combustion gave 0.4655 g of carbon dioxide and 0.2533 g of water. Determine the percentage composition of the compound.

Q2

An organic compound was analysed by Duma’s method. 0.45 g of the compound on combustion gave 48.6 ml nitrogen at 27oC and 756 mm pressure. Calculate the percentage of nitrogen.

Q3

An organic compound on analysis gave the data : 0.25 g of the compound on complete combustion gave 0.37 g of CO2 and 0.2 g of water.

Q4

0.2 g of an organic compound was analysed by Kjeldahl’s method. Ammonia evolved was absorbed in 60 ml N/5 H2SO4. Unused acid required 40 ml of N/10 NaOH for complete neutralisation. Find the percentage of nitrogen in the compound.

Q5

1.216 g of an organic compound was reacted under Kjeldahl’s method and ammonia evolved was absorbed in 100 ml N H2SO4. The remaining acid solution was made up to 500 ml by addition of water 20 ml of this dilute solution required 32 ml of N/10 caustic soda solution for complete neutralisation. Calculate the percentage of nitrogen in the compound. 

Q6

0.5264 g silver bromide is obtained from 0.5124 g of an organic compound. Calculate the percentage of bromine in the compound.

Q7

0.156 g of an organic compound on heating with fuming HNO3 and AgNO3 gives 0.235 g of AgI. Calculate the percentage of the iodine in the compound.

Q8

0.1170 g of an organic compound on heating with conc. HNO3 and silver nitrate in Carius furnace gave 0.42 g of AgCl. Find the percentage of chlorine in the compound.

Q9

On heating 0.32 g of an organic compound with concentrated nitric acid and barium chloride, 0.932 g barium sulphate was obtained. Calculate the percentage of sulphur in the given compound.