Lakhmir Singh and Manjit Kaur Solutions for Chapter: Atoms and Molecules, Exercise 1: Very Short Answer Type Questions

A liquid compound $\mathrm{X}$ of molecular mass $18 \mathrm{u}$ can be obtained from a number of natural sources. All the animals and plants need liquid $\mathrm{X}$ for their survival. When an electric current is passed through $200 \mathrm{grams}$ of pure liquid $\mathrm{X}$ under suitable conditions, then $178 \mathrm{grams}$ of gas $\mathrm{Y}$ and $22 \mathrm{grams}$ of gas $\mathrm{Z}$ are produced. Gas $\mathrm{Y}$ is produced at the positive electrode whereas gas $\mathrm{Z}$ is obtained at the negative electrode. Moreover, gas $\mathrm{Y}$ supports combustion whereas gas $\mathrm{Z}$ burns itself causing explosions. 

Which law of chemical combination is illustrated by this example?

A liquid compound $\mathrm{X}$ of molecular mass $18 \mathrm{u}$ can be obtained from a number of natural sources. All the animals and plants need liquid $\mathrm{X}$ for their survival. When an electric current is passed through $200 \mathrm{grams}$ of pure liquid $\mathrm{X}$ under suitable conditions, then $178 \mathrm{grams}$ of gas $\mathrm{Y}$ and $22 \mathrm{grams}$ of gas $\mathrm{Z}$ are produced. Gas $\mathrm{Y}$ is produced at the positive electrode whereas gas $\mathrm{Z}$ is obtained at the negative electrode. Moreover, gas $\mathrm{Y}$ supports combustion whereas gas $\mathrm{Z}$ burns itself causing explosions.

Name two sources of liquid $\mathrm{X}$.

A liquid compound $\mathrm{X}$ of molecular mass $18 \mathrm{u}$ can be obtained from a number of natural sources. All the animals and plants need liquid $\mathrm{X}$ for their survival. When an electric current is passed through $200 \mathrm{grams}$ of pure liquid $\mathrm{X}$ under suitable conditions, then $178 \mathrm{grams}$ of gas $\mathrm{Y}$ and $22 \mathrm{grams}$ of gas $\mathrm{Z}$ are produced. Gas $\mathrm{Y}$ is produced at the positive electrode whereas gas $\mathrm{Z}$ is obtained at the negative electrode. Moreover, gas $\mathrm{Y}$ supports combustion whereas gas $\mathrm{Z}$ burns itself causing explosions. 

State an important use of $\mathrm{Y}$ in our life.

One of the forms of a naturally occurring solid compound $\mathrm{P}$ is usually used for making the floor of houses. On adding a few drops of dilute hydrochloric acid to $\mathrm{P}$, brisk effervescence is produced. When $50 \mathrm{g}$ of reactant $\mathrm{P}$ was heated strongly, then $22 \mathrm{g}$ of a gas $\mathrm{Q}$ and $28 \mathrm{g}$ of solid $\mathrm{R}$ were produced as products. Gas $\mathrm{Q}$ is the same which produced brisk effervescence on adding dilute $\mathrm{HCl}$ to $\mathrm{P}$. Gas $\mathrm{Q}$ is said to cause global warming whereas solid $\mathrm{R}$ is used for whitewashing.

What is (i) Solid $\mathrm{P}$

             (ii) Gas $\mathrm{Q}$

             (iii) Solid $\mathrm{R}$

One of the forms of a naturally occurring solid compound $\mathrm{P}$ is usually used for making the floor of houses. On adding a few drops of dilute hydrochloric acid to $\mathrm{P}$, brisk effervescence are produced. When $50 \mathrm{g}$ of reactant $\mathrm{P}$ was heated strongly, than $22 \mathrm{g}$ of a gas $\mathrm{Q}$ and $28 \mathrm{g}$ of solid $\mathrm{R}$ were produced as products. Gas $\mathrm{Q}$ is the same which produced brisk effervescence on adding dilute $\mathrm{HCl}$ to $\mathrm{P}$. Gas $\mathrm{Q}$ is said to cause global warming whereas solid $\mathrm{R}$ is used for white-washing.

What is the total mass of $\mathrm{Q}$ and $\mathrm{R}$ obtained from $50 \mathrm{g}$ of $\mathrm{P}$?

One of the forms of a naturally occurring solid compound $\mathrm{P}$ is usually used for making the floor of houses. On adding a few drops of dilute hydrochloric acid to $\mathrm{P}$, brisk effervescence are produced. When $50 \mathrm{g}$ of reactant $\mathrm{P}$ was heated strongly, than $22 \mathrm{g}$ of a gas $\mathrm{Q}$ and $28 \mathrm{g}$ of solid $\mathrm{R}$ were produced as products. Gas $\mathrm{Q}$ is the same which produced brisk effervescence on adding dilute $\mathrm{HCl}$ to $\mathrm{P}$. Gas $\mathrm{Q}$ is said to cause global warming whereas solid $\mathrm{R}$ is used for white-washing.

How does the total mass of $\mathrm{Q}$ and $\mathrm{R}$ formed, compare with the mass of $\mathrm{P}$ taken?

One of the forms of a naturally occurring solid compound $\mathrm{P}$ is usually used for making the floor of houses. On adding a few drops of dilute hydrochloric acid to $\mathrm{P}$, brisk effervescence are produced. When $50\mathrm{g}$ of reactant $\mathrm{P}$ was heated strongly, than $22\mathrm{g}$ of a gas $\mathrm{Q}$ and $28\mathrm{g}$ of solid $\mathrm{R}$ were produced as products. Gas $\mathrm{Q}$ is the same which produced brisk effervescence on adding dilute $\mathrm{HCl}$ to $\mathrm{P}$. Gas $\mathrm{Q}$ is said to cause global warming whereas solid $\mathrm{R}$ is used for white-washing.

What conclusion do you get from the comparison of masses of products and reactant? 

One of the forms of a naturally occurring solid compound $\mathrm{P}$ is usually used for making the floor of houses. On adding a few drops of dilute hydrochloric acid to $\mathrm{P}$, brisk effervescence are produced. When $50 \mathrm{g}$ of reactant $\mathrm{P}$ was heated strongly, than $22 \mathrm{g}$ of a gas $\mathrm{Q}$ and $28 \mathrm{g}$ of solid $\mathrm{R}$ were produced as products. Gas $\mathrm{Q}$ is the same which produced brisk effervescence on adding dilute $\mathrm{HCl}$ to $\mathrm{P}$. Gas $\mathrm{Q}$ is said to cause global warming whereas solid $\mathrm{R}$ is used for white-washing.

Which law of combination is illustrated by the example given in this problem?