Tag: some important compounds of magnesium and calcium

Questions Related to some important compounds of magnesium and calcium

Beryllium is placed above magnesium in the group II. Beryllium dust, therefore, when added to $MgCl {2}$ solution will ____________.

  1. have no effect

  2. precipitate Mg metal

  3. precipitate MgO

  4. lead to dissolution of Be metal


Correct Option: A

Mixture of $MgCl _2$ and MgO is called :

  1. Portland cement.

  2. Sorel's cement.

  3. double salt.

  4. None of these.


Correct Option: B
Explanation:

Mixing solid MgO  with MgCl2  produces Sorrel cement

Epsom salt is:

  1. ${ CuSO } _{ 4 }$

  2. ${ CaSO } _{ 4 }$

  3. ${ MgSO } _{ 4 }.7H _2O$

  4. ${ Na } _{ 2 }{ SO } _{ 4 }$


Correct Option: C
Explanation:

It is often encountered as the heptahydrate sulfate mineral epsomite commonly called Epsom salt${ MgSO } _{ 4 }\cdot { 7H } _{ 2 }O$. It has enormous health benefits.

Name a compound which hardens on wetting with water.

  1. Calcium sulphate decahydrates

  2. Calcium sulphur hemihydrates

  3. Calcium sulphate

  4. Hydrated calcium sulphate


Correct Option: B
Explanation:

The calcium compound that hardens on wetting with water is commonly known as Plaster of Paris (POP), chemically known as calcium sulphate hemihydrate having the formula $CaSO _4.1/2H _2O$

The reaction between marble and dilute $H _2SO _4$ is not used to prepare carbon dioxide for laboratory purpose.
Answer whether the above statement is true or false.

  1. True

  2. False


Correct Option: A
Explanation:

Insoluble $CaSO _4$ is formed which deposits on the surface of marble and prevent the further action of dilute $H _2SO _4$, so the evolution of $CO _ 2$ ceases after some time.

The weight of magnesium increases on burning.

  1. True

  2. False


Correct Option: A
Explanation:

Burning of magnesium, it combines with atmospheric oxygen to produce $MgO$. Thus mass gets increased on combustion.

$Mg +O _2$ $\rightarrow$ $MgO\ +$ light and heat

In paper industry, the chemical compound used for bleaching is :

  1. potassium sulphite

  2. calcium sulphate

  3. sulphuric acid

  4. calcium bisulfite


Correct Option: D
Explanation:

A bleaching agent is a material that lightens or whitens a substrate through chemical reaction. The bleaching reactions usually involve oxidative or reductive processes that degrade color systems In paper industry, the chemical compound used for bleaching is calcium bisulphate. 

How can Calcium Sulphate be produced from $Ca _3(PO _4) _2$ ?

  1. Reacting with Sulphuric acid

  2. Reacting with Sulphur

  3. Reacting with Sulphur trioxide

  4. Reacting with Sulphur dioxide


Correct Option: A
Explanation:

When Calcium Phosphate is treated with Sulphuric Acid, Calcium Sulphate is obtained as a precipitate along with the formation of Phosphoric Acid. The balanced equation can be written as-
$Ca _3(PO _4) _2$ $+$ $3H _2SO _4$ $=$ $2H _3PO _4$ $+$ $3CaSO _4$

How is ${MgSO} _{4}$ produced from ${MgCO} _{3}$?

  1. ${MgCO} _{3}$${+}$ ${S}$

  2. ${MgCO} _{3}$${+}$ ${SO} _{2}$

  3. ${MgCO} _{3}$${+}$ ${SO} _{3}$

  4. ${MgCO} _{3}$ ${+}$ ${H} _{2}{SO} _{4}$


Correct Option: D
Explanation:

Magnesium Sulphate is produced from Magnesium carbonate by reacting the carbonate with Sulphuric acid. The balanced equation can be written as-
${MgCO} _{3}$${+}$ ${H} _{2}{SO} _{4}$  ${=}$ ${MgSO} _{4}$ ${+}$ ${CO} _{2}$ ${+}$ ${H} _{2}{O}$

What is the chemical formula of Gypsum?

  1. ${CaSO} _{4}$${.}$${5H} _{2}{O}$

  2. ${CaSO} _{4}$${.}$${7H} _{2}{O}$

  3. ${CaSO} _{4}$${.}$${2H} _{2}{O}$

  4. ${CaSO} _{4}$${.}$${9H} _{2}{O}$


Correct Option: C
Explanation:

The chemical formula of Gypsum is ${CaSO} _{4}$${.}$${2H} _{2}{O}$. It contains two moles of water in it. It can also be said as Calcium Sulphate dihydrate.