Laws of Chemical Combination MCQ basic

Laws of Chemical Combination-MCQ-Basic Level

Dear Readers,

Compared to other sections, Chemistry is considered to be the most scoring section. If prepared thoroughly, chemistry can help students to secure a meritorious position in the exam. These questions are very important in achieving your success in Exams after 12th.

Q1. 1.0 g of an oxide of A contained 0.5 g of A. 4.0 g of another oxide of A contained 1.6 g of A. The data indicate the law of

•  Reciprocal proportions
•  Constant proportions
•  Conservation of energy
•  Multiple proportions

The above data indicated the Law of Multiple proportions.

Q2. Irrespective of the source, pure sample of water always yields 88.89% mass of oxygen and 11.11% mass of hydrogen. This is explained by the law of

•  Conservation of mass
•  Constant composition
•  Multiple proportions
•  Constant volume

Above Statement explains the Law of Constant Composition.

Q3. Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates

•  Law of reciprocal proportions
•  Law of constant proportions
•  Law of multiple proportions
•  Law of equivalent proportions

The above data indicates Law of multiple proportions.

Q4. The law of multiple proportions was proposed by

•  Lavoisier
•  Dalton
•  Proust
•  Gay-Lussac

The law of multiple proportions was proposed by Dalton.

Q5. Avogadro number is

•  Number of atoms one gram of element
•  Number of milli litres which one mole of a gaseous substances occupies at NTP
•  Number of molecules present in one gram molecular mass of a substance
•  All of these

Number of molecules present in one gram molecular mass of a substance

Q6. Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively 12 : 16 and 12 : 32. These figures illustrate the

•  Law of multiple proportions
•  Law of reciprocal proportions
•  Law of conservation of mass
•  Law of constant proportions

Law of multiple proportions.

Q7. The law of multiple proportions is illustrated by the two compounds

•  Sodium chloride and sodium bromide
•  Ordinary water and heavy water
•  Caustic soda and caustic potash
•  Sulphur dioxide and sulphur trioxide

Sulphur dioxide and sulphur trioxide

Q8. One sample of atmospheric air is found to have 0.03% of carbon dioxide and another sample 0.04%. this is evidence that

•  The law of constant composition is not always true
•   The law of multiple proportions is true
•  Air is a compound
•  Air is a mixture

Air is a Mixture

Q9. After a chemical reaction, the total mass of reactants and products

•  Is always increased
•  Is always decreased
•  Is not changed
•  Is always less or more

the total mass of reactants and products remains same before and after a chemical reaction.

Q10. The law of definite proportions is not applicable to nitrogen oxide because

•  Nitrogen atomic weight is not constant
•  Nitrogen molecular weight is variable
•  Nitrogen equivalent weight is variable
•  Oxygen atomic weight is variable

Nitrogen equivalent weight is variable