Tag: the s-block elements

Questions Related to the s-block elements

Which of the following metals is present in chlorophyll?

some important compounds of magnesium and calcium the s-block elements chemistry

  1. $Mg$

  2. $Be$

  3. $Ca$

  4. None of above

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Correct Option: A

Magnesium burns in carbon dioxide giving the products. The formula of the products are :

some important compounds of magnesium and calcium the s-block elements chemistry

  1. MgO,C

  2. Mg,CO

  3. $MgO _{2}$,C

  4. $Mg(OH) _{2} ,O _{2}$

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Correct Option: A
Explanation:

Reaction:
$2Mg+CO _2\rightarrow 2MgO+C$

When magnesium burns in carbon dioxide, it forms magnesium oxide and carbon as a product.

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

some important compounds of magnesium and calcium the s-block elements chemistry

  1. have no effect

  2. precipitate Mg metal

  3. precipitate MgO

  4. lead to dissolution of Be metal

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Correct Option: A

Mixture of $MgCl _2$ and MgO is called :

some important compounds of magnesium and calcium the s-block elements chemistry

  1. Portland cement.

  2. Sorel's cement.

  3. double salt.

  4. None of these.

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Correct Option: B
Explanation:

Mixing solid MgO  with MgCl2  produces Sorrel cement

Epsom salt is:

some important compounds of magnesium and calcium the s-block elements chemistry

  1. ${ CuSO } _{ 4 }$

  2. ${ CaSO } _{ 4 }$

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

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

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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.

some important compounds of magnesium and calcium the s-block elements chemistry

  1. Calcium sulphate decahydrates

  2. Calcium sulphur hemihydrates

  3. Calcium sulphate

  4. Hydrated calcium sulphate

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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.

some important compounds of magnesium and calcium the s-block elements chemistry

  1. True

  2. False

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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.

some important compounds of magnesium and calcium the s-block elements chemistry

  1. True

  2. False

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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 :

some important compounds of magnesium and calcium the s-block elements chemistry

  1. potassium sulphite

  2. calcium sulphate

  3. sulphuric acid

  4. calcium bisulfite

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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 $Ca _3(PO _4) _2$ ?

some important compounds of magnesium and calcium the s-block elements chemistry

  1. Reacting with Sulphuric acid

  2. Reacting with Sulphur

  3. Reacting with Sulphur trioxide

  4. Reacting with Sulphur dioxide

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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-
$Ca _3(PO _4) _2$ $+$ $3H _2SO _4$ $=$ $2H _3PO _4$ $+$ $3CaSO _4$