Question

220 g of dry ice is put in 456 g of carbon disulphide. The total number of atoms of carbon in the solution is:
i) 10NA
ii) 12NA
iii) 11NA
iv) 15NA
​

Answer 1

Given - Weight of dry ice - 220 gram

Weight of carbon disulphide - 456 gram

Find - Total number of carbon atoms.

Solution - One mole of substance contains atoms equal to Avogadro's number (NA).

Dry ice refers to solid carbon dioxide.

44 gram of carbon dioxide is 1 mole.

220 gram of carbon dioxide will be - 5 moles.

1 mole contains of carbon dioxide contains 1NA atoms of carbon.

Hence, 5 mole will have, 5NA atoms of carbon.

Molecular weight of carbon disulphide is 76 gram.

76 gram of carbon disulphide is 1 mole.

456 gram of carbon disulphide will be - 6 moles.

As per above calculations, 6NA atoms of carbon will be present.

Therefore, 6NA + 5NA will be 11NA.

Hence, iii) 11NA is the correct answer.