Tag: some important compounds of magnesium and calcium

Questions Related to some important compounds of magnesium and calcium

A metal $M$ readily forms its sulphate $MSO _{4}$ which is water soluble. It forms its oxide $MO$ which becomes inert on heating. It forms an insoluble hydroxide $M(OH) _{2}$ which is soluble in $NaOH$ solution. Then M is:

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

  1. $Mg$

  2. $Ba$

  3. $Ca$

  4. $Be$

Show answer
Correct Option: D
Explanation:

In the periodic table, on moving down, water solubility of alkaline earth metal decreases. Oxides and hydroxides of alkaline earth metal are basic except Be which is amphoteric.
Hence the metal M is Be.
conclusion: hence the option (D) is correct.

Several blocks of magnesium are fixed to the bottom of a ship to:

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

  1. make the ship lighter

  2. prevent action of water and salt

  3. prevent puncturing by under-sea rocks

  4. keep away the sharks

Show answer
Correct Option: A
Explanation:

Several blocks of magnesium are fixed to the bottom of a ship to. Magnesium, on account of its lightness, great affinity for oxygen and toughness is used in ship. Being a lighter element, magnesium makes the ship lighter when it is fixed to the bottom of the ship.

Hence option A is correct answer.

Gypsum is not chemically similar to:

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

  1. Selenite

  2. Alabaster

  3. Anhydrite

  4. Zlnorsper

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Correct Option: D
Explanation:

Gypsum is calcium sulphate dihydrate $(CaSO _4 \cdot 2H _2O)$. Zlnorsper is not chemically similar to gypsum.

Potash magnerin is:

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

  1. $KCO _{ 3}.MgCO _{ 3} .5H _{2} O$

  2. $K _{2} SO _{4} .MgSO _{4} .6H _{2} O$

  3. $KCl.MgCl _{2} .6H _{2} O$

  4. none

Show answer
Correct Option: B
Explanation:

The formula of Potash magnerin is $K _{2} SO _{4} .MgSO _{4} .6H _{2} O$

Dead burnt plaster is :

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

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

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

  3. ${ CaSO } _{ 4 }.1/2{ H } _{ 2 }O$

  4. ${ CaSO } _{ 4 }$

Show answer
Correct Option: D
Explanation:

When Plaster of Paris $CaSO _4.\dfrac{1}{2}H _2O$ is heated above 393 K, its water of crystallisation is lost and anhydrous Calcium sulphate is left that is known as a dead burnt plaster.

Hence option D is correct answer.

When heated in steam, Mg burns brilliantly producing:

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

  1. $Mg(OH) _2$

  2. $MgO and H _2$

  3. $MgO and O _2$

  4. $MgO and O _3$

Show answer
Correct Option: B
Explanation:

Magnesium burns in steam to produce white magnesium oxide and hydrogen gas. Very clean magnesium ribbon has a very slight reaction with cold water. After several minutes, some bubbles of hydrogen form on its surface, and the coil ofmagnesium ribbon usually floats to the surface.

The reaction occurs is,
$Mg+H _2O (g) \rightarrow MgO +H _2$

Hence option B is correct answer.

Which of the following is called milk of magnesia?

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

  1. Suspension of ${\rm{Mg}}{\left( {{\rm{OH}}} \right) _{\rm{2}}}$

  2. Solution of ${\rm{MgS}}{{\rm{O}} _4}$

  3. Suspension of ${\rm{Mg}}$

  4. Solution of ${\rm{Mg}}{\left( {{\rm{HC}}{{\rm{O}} _3}} \right) _2}$

Show answer
Correct Option: A
Explanation:

Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)₂. It occurs in nature as the mineral brucite.

Milk of magnesia contains magnesium, which is a naturally occurring mineral. The human body requires magnesium to help many of its systems function properly, most notably the muscles and the nerves.

Product (S) are :

$Mg _2C _3 {\xrightarrow []{D _2O} } \,\, { \xrightarrow[2.H _2O/\bar{O}H]{1.BH _3.THf}} \,\,{\xrightarrow {H _2/Ni} }\,\, \xrightarrow[\Delta]{Conc.H _3PO _4} (S)$

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

  1. ${\text{H}}\mathop {\text{C}}\limits _{\mathop {\text{D}}\limits^{\text{|}} } = {\text{CH - C}}{{\text{D}} _{\text{3}}}$

  2. ${{\text{H}} _2}\mathop {\text{C}}\limits _{\mathop {\text{D}}\limits^{\text{|}} } - {\text{CH}}\;{\text{ = }}\;{\text{C}}{{\text{D}} _2}\;\;$

  3. ${{\text{H}} _{\text{2}}}{\text{C}}\; = {\text{CH - C}}{{\text{H}} _{\text{3}}}$

  4. ${{\text{H}} _{\text{2}}}{\text{C}} = \mathop {\text{C}}\limits _{\mathop {\text{D}}\limits^{\text{|}} } - {\text{C}}{{\text{H}} _{\text{3}}}$

Show answer
Correct Option: A

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

Show answer
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.