Chapter 4, Problem 20STP

Interpretation Introduction

Interpretation:

Whether Statement I and Statement II are true or false and whether statement-II is the correct explanation for statement-I needs to be determined.

Concept introduction:

Carbon monoxide is an odorless, colorless, poisonous gas that is made of one carbon and one oxygen atom. Carbon dioxide is made of one carbon and two oxygen atoms.

Answer to Problem 20STP

Statement-I is true, statement II is true. But, statement-II is not the correct explanation of statement I.

Explanation of Solution

Reason for true statements: Statement-I. Carbon and oxygen can form either CO or $C{O}_2$ due to the combustion of carbon.

Carbon and oxygen combine to form two gases. When there is complete combustion of carbon, carbon dioxide $C{O}_2$ is produced. When there is incomplete combustion of carbon due to the limited supply of air, only half of the oxygen is added to the carbon, thus carbon monoxide (CO) is produced.

Statement-II-Carbon and oxygen obey the law of definite composition. The statement is correct because in 1 compound C and O are always present in definite composition.

But statement II is not correct reason for statement I. The correct reason for statement 1 based on law of multiple proportions according to which when two elements combine to form two or more chemical compounds, the mass of one element combined with a fixed mass of the other, bears a simple ratio to one another.

Conclusion

Statement-I is true, statement II is true. But, statement-II is not the correct explanation of statement I.