Tag: substances in common use

Questions Related to substances in common use

The definite number of water molecules which enters into a chemical combination with the substance when the substance is crystallized from its hot saturated solution is called ________. 

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. crystallization

  2. water of crystallization

  3. formation of water molecule

  4. none of the above

Show answer
Correct Option: B
Explanation:

The definite number of water molecules which enters into a chemical combination with the substance when the substance is crystallized from its hot saturated solution is called water of crystallization.

A salt associated with water of crystallization is known as a:

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. acid

  2. buffer

  3. hydrate

  4. anion

Show answer
Correct Option: C
Explanation:

A salt associated with the water of crystallization is known as a hydrate. The structure of hydrates can be quite elaborate, because of the existence of hydrogen bonds that define polymeric structures.


Hence, the correct option is $\text{C}$

Water of crystallization is present in a definite :

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. shape

  2. ratio

  3. volume

  4. size

Show answer
Correct Option: B
Explanation:

Water of crystallization or water of hydration or crystallization water is water that occurs inside crystals. Water is often necessary for the formation of crystals. Water of crystallization is the total weight of water in a substance at a given temperature and is mostly present in a definite (stoichiometric) ratio.

Heated calcium sulphate with half a water of crystallization is commonly called as :

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. washing soda

  2. plaster of paris

  3. naushadar salt

  4. bleaching powder

Show answer
Correct Option: B
Explanation:

Plaster of paris which is chemically called calcium sulphate hemihydrate. Since, it is brought to use from paris, called as "plaster of paris". It is prepared by heating of gypsum at 373K. 

Since there are 10 water molecules in washing soda, hence it is known as:

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. sodium bicarbonate decahydrate

  2. sodium carbonate decahydrate

  3. sodium bicarbonate nanohydrate

  4. sodium decahydrate

Show answer
Correct Option: B
Explanation:

Washing soda is called sodium carbonate. Since, there are $10$ water molecules in washing soda, hence it is known as sodium carbonate decahydrate.

Potash alum contains ___________ number of water molecules.

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. 24

  2. 22

  3. 20

  4. 25

Show answer
Correct Option: A
Explanation:

Potash Alum $(K _2SO _4 Al _2 (SO _4) _3 .24H _2O)$ is a colourless, odourless and crystalline substance. Its crystals are prepared by mixing concentrated solutions of potassium sulphate and aluminium sulphate. It is soluble in water. It contains 24 molecules of water.

Copper sulphate pentahydrate is commonly called as____, whereas ferrous sulphate heptahydrate is commonly called as _____ .

chemistry substances in common use percent composition water of crystallisation percentage composition and empirical formula

  1. white vitriol, blue vitriol

  2. green vitriol, blue vitriol

  3. blue vitriol, green vitriol

  4. blue vitriol, white vitriol

Show answer
Correct Option: C
Explanation:

Copper sulphate pentahydrate ($CuSO _4.5H _2O$) commonly known as blue vitrol contains 5 water molecules which gives it a blue color. Similarly, the green color of ferrous sulphate heptahydrate ($FeSO _4.7H _2O$) is due to 7 molecules water present in it. This water is responsible for the geometric shape and color of the crystals.

Which of the following is not a use of baking soda?

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. In medicines as antacid

  2. As a component of baking powder

  3. In removing permanent hardness of water

  4. In fire extinguishers

Show answer
Correct Option: C
Explanation:

Baking soda,$(NaHCO _3)$ also known as sodium bicarbonate, is widely used in baking. This is because it has leavening properties, meaning it causes dough to rise by producing carbon dioxide. Aside from cooking, baking soda has a variety of additional household uses and health benefits.

They are-
  • In medicines as antacid
  • As a component of baking powder
  • In fire extinguishers
  • Relieves insect bites
  • Relieves skin irritation
  • Air Freshener
  • Hence, option C is wrong about baking soda as it is not used in removing permanent hardness of water.

In Solvay ammonia process, sodium bicarbonate is precipitated due to :

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. presence of $NH _3$

  2. reaction with $CO _2$

  3. reaction with brine solution

  4. reaction with NaOH

Show answer
Correct Option: C
Explanation:

In Solvay process, sodium bicarbonate is precipitated due to common ion$(Na^+)$ effect provided by brine (concentrated NaCl Solution).

The chemical name of baking soda is:

chemistry substances in common use preparation, properties and uses of baking soda chemical from common salt compounds of carbon

  1. sodium hydrogen carbonate

  2. sodium carbonate

  3. sodium bisulphite

  4. none of the above

Show answer
Correct Option: A
Explanation:

Baking soda is also known as sodium hydrogen carbonate.

Thus its chemical formula will be: $NaHCO _3$