Tag: some important compounds of magnesium and calcium

Questions Related to some important compounds of magnesium and calcium

Magnesium oxide is produced by the calcination of magnesium phosphate or magnesium sulphate by the treating magnesium chloride with lime followed by heat.

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

  1. True

  2. False

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Correct Option: B
Explanation:

It is produced by the calcination of magnesium carbonate or magnesium hydroxide.The latter is obtained by the treatment of magnesium chloride solutions, typically seawater, with lime.

How can Calcium Suphate be produced from Calcium Fluoride?

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

  1. ${CaF} _{2}$ ${+}$ ${H} _{2}{SO} _{4}$

  2. ${CaF} _{2}$ ${+}$ ${SO} _{2}$

  3. $CaF _2 + H _2S$

  4. None of these

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Correct Option: A
Explanation:

Calcium Fluoride is treated with Sulphuric Acid to give Hydrogen Fluoride and a precipitate of Calcium Sulphate. The balanced equation can be written as-
${CaF} _{2}$ ${+}$ ${H} _{2}{SO} _{4}$ ${=}$ ${2HF}$ ${+}$ ${CaSO} _{4}$

Which of the following statement about magnesium oxide is/are correct?

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

  1. It is a relatively poor desiccant

  2. The largest consumer of magnesia is refractory industry

  3. It is used for making Portland cement

  4. In medicine, magnesium oxide is used for relief of heartburn and sour stomatch

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Correct Option: A,B,C,D

Magnesium on heating in air gives $(A)$ and $(B)$. On reaction with water $(B)$ gives colourless gas $(C)$. $(C)$ when passed through $CuSO _4$ solution gives a blue coloured solution $(D)$. The blue solution is:

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

  1. $MgO$

  2. $Mg _3N _2SO _3.H _2O$

  3. $NH _3$

  4. $[Cu(NH _3) _4]SO _4.H _2O$

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Correct Option: D
Explanation:

Option $(D)$ is correct.

Magnesium on strong heating reacts with nitrogen of air.
$Mg + O _2 \rightarrow MgO  [A] + Mg _3N _2 [B]$
$Mg _3N _2 [B]  + H _2O \rightarrow Mg(OH) _2 + NH _3 [C]$
$ NH _3 + CuSO _4(aq) \rightarrow [Cu(NH _3) _4]SO _4.H _2O [D]$

$MgO$ when mixed with a saturated solution of $MgCl _2$ sets to a hard mass known as 'sorel cement'. The composition of sorel cement is $MgCl _2.nMgO.xH _2O$. The value of $n$ is:

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

  1. 2

  2. 5

  3. 3

  4. 1

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Correct Option: C
Explanation:

There are two types of sorel cement 3 phase and 5 phase.

$MgCl _2.3Mg(OH) _2.8H _2O$ is 3 phase sorel cement.