Tag: law of multiple proportions

Questions Related to law of multiple proportions

Among the following pairs of compounds, the one that illustrates the law of multiple proportions is:

  1. $NH _{3}$ and $NCl _{3}$

  2. $H _{2}S$ and $SO _{2}$

  3. $CuO$ and $Cu _{2}O$

  4. $CS _{2}$ and $FeSO _{4}$


Correct Option: C
Explanation:

According to the concept of law of multiple proportions, if two elements chemically combine to give two or more compounds, then the weight of one element which combines with the fixed weight of the other element in those compound, bear simple multiple ratios to one another.


Hence, $CuO$ and $CU _2O$ form two different compounds in a ratio of 1:2 with the fixed weight of oxygen.

The % composition of four hydrocarbons are as follows:


(i) (ii) (iii) (iv)
%C 75 80 85.7 91.3
%H 25 20 14.3 8.7


The data illustrates the law of:

  1. constant proportion

  2. conservation of mass

  3. multiple proportion

  4. reciprocal proportion


Correct Option: C

The laws of multiple proportion was proposed by :

  1. Lavoisier

  2. Dalton

  3. Proust

  4. Gay Lussac


Correct Option: B
Explanation:

The British scientist, John Dalton proposed the Law of Multiple Proportion.

The % of hydrogen in water and hydrogen peroxide is $11.2$ % and $5.94$ % respectively. This illustrates the law of:

  1. constant proportions

  2. conservation of mass

  3. multiple proportions

  4. law of gaseous volume.


Correct Option: C
Explanation:

The law of multiple proportions say that if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers. 

The oxides of nitrogen contain 63.65%, 46.69% and 30.46% of nitrogen by weight, respectively. This data illustrates the law of:

  1. constant proportions

  2. multiple proportions

  3. reciprocal proportions

  4. conservation of mass


Correct Option: B
Explanation:

The law of multiple proportions say that If two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.
Here, the ratios of oxygen which react with a constant mass of N are $2:3 , 2:1$ and $4:3$ respectively.

The ratio between the different weights of oxygen in different compounds which combine with the same weight of nitrogen ($14$ parts) is $8:16:24:32:40$ or $1:2:3:4:5$.
This is simple whole number which supports the law of:

  1. conservation of mass

  2. multiple proportion

  3. constant composition

  4. reciprocal proportion


Correct Option: B
Explanation:

The answer is multiple proportion.
When two elements combine to from two or more than two compounds, the weights of one of the element which combine with a fixed weight of the other, bear a simple whole number ratio is the law of multiple proportion and the given example supports the law.

Different proportions of oxygen in the various oxides of nitrogen proves the law of:

  1. equivalent proportions

  2. conservation of mass

  3. multiple proportions

  4. constant proportions


Correct Option: C

0.75 mole of solid ‘$A _4$’ and 2 moles of gaseous $O _2$ are heated in a sealed vessel, completely using up the reactants and producing only one compound. It is found that when the temperature is reduced to the initial temperature, the contents of the vessel exhibit a pressure equal to half the original pressure. What conclusions can be drawn from these data the product of the reaction?

  1. $A _2O _5$

  2. $A _3O _4$

  3. $A _2O _2$

  4. none of these


Correct Option: B
Explanation:
give reaction
$A _4(s) + O _2(g) → A _xO _y$

Applying POAC  law for A atoms,
4 × moles of $A _4  =  x \times moles of A _xO _y$
=> $4 \times 0.75 = x \times  1$
=> x = 3

Applying POAC for O atoms,
$2\times  moles of O _2 = y \times moles of A _xO _y$
=> $2 \times 2 = y \times 1$
=> y = 4

Thus, the formula of the product is $A _3O _4$.

The law of multiple proportion was discovered by:

  1. John Dalton

  2. Richter

  3. Joseph Proust

  4. A. Lavoisier


Correct Option: A
Explanation:

John Dalton discovered the law of multiple proportion.

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

  1. reciprocal proportions

  2. constant proportions

  3. multiple proportions

  4. equivalent proportions


Correct Option: C
Explanation:

The law of multiple proportions say that If two elements form more than one compounds between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.