Question

The statements for laws of chemical combinations are given below. Mark the statement which is not correct.
A. Matter can neither be created nor destroyed: Law of conservation of mass
B. A compound always contains exactly the same proportion of elements by weight: Law of definite proportions
C. When gases combine they do so in a simple ratio by weight: Gay Lussac's Law
D. Equal volumes of gases at same temperature and pressure contain same number of molecules: Avogadro's Law

Answer 1

Hint: To find the correct statement we need to analyze the laws that are mentioned. Once analyzed we are required to compare the mentioned statements as options.

Complete step-by-step answer:
Law of Conservation of Mass states that matter can neither be created nor destroyed. The total mass, that is, the sum of the mass of the reacting mixture and the products formed remains constant.

Law of Definite Proportions states that the proportion of elements by weight in a given compound will always remain exactly the same.

Gay Lussac's Law of Gaseous Volume states that in a gaseous system, when the reactions combine together they always do so in volumes which bear a simple ratio to one another and to the volume of the products, under similar conditions of temperature and pressure.

Avogadro's Law states that under the same conditions of temperature and pressure, the equal volume of all the gases contains an equal number of molecules.

Statement C is for the Law of Definite Proportion.

So, the correct option is Option C.

Note: Gay Lussac's Law of Gaseous Volume which is the correct answer to the question, can also be defined in another way. The law states that the pressure of an enclosed ideal gas is directly proportional to its temperature at the constant volume of the gas. This law is also known as a pressure law because it relates the pressure of a gas to the temperature of the gas.