Tag: substances in common use

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Questions Related to substances in common use

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

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 ________. 

  1. crystallization

  2. water of crystallization

  3. formation of water molecule

  4. none of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. acid

  2. buffer

  3. hydrate

  4. anion
Reveal answer Fill a bubble to check yourself
C Correct answer
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 $\text{C}$

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

Water of crystallization is present in a definite :

  1. shape

  2. ratio

  3. volume

  4. size
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  1. washing soda

  2. plaster of paris

  3. naushadar salt

  4. bleaching powder
Reveal answer Fill a bubble to check yourself
B Correct answer
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. 

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

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

  1. sodium bicarbonate decahydrate

  2. sodium carbonate decahydrate

  3. sodium bicarbonate nanohydrate

  4. sodium decahydrate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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

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

Potash alum contains ___________ number of water molecules.

  1. 24

  2. 22

  3. 20

  4. 25
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. white vitriol, blue vitriol

  2. green vitriol, blue vitriol

  3. blue vitriol, green vitriol

  4. blue vitriol, white vitriol
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. In medicines as antacid

  2. As a component of baking powder

  3. In removing permanent hardness of water

  4. In fire extinguishers
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. presence of $NH _3$
  2. reaction with $CO _2$

  3. reaction with brine solution

  4. reaction with NaOH
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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