Tag: some important compounds of magnesium and calcium

Questions Related to some important compounds of magnesium and calcium

Give chemical name and nature (acidic or basic) of the ash formed by burning of a $Mg$ ribbon in the air? 

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

  1. magnesium chloride, acidic

  2. magnesium nitrite, basic

  3. magnesium oxide, acidic

  4. magnesium oxide, basic

Show answer
Correct Option: D
Explanation:
Option $(D)$ is correct.
Magnesium oxide is formed as ash by burning of $Mg$ ribbon in the air. This is an exothermic reaction.
$2Mg + O _2 \rightarrow 2MgO + \:energy$
Magnesium oxide is basic in nature as it reacts with water to form magnesium hydroxide which is a base.

Oxide used to treat indigestion and relieve pain is:

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

  1. magnesium hydroxide

  2. magnesium oxide

  3. calcium oxide

  4. both $A$ and $B$

Show answer
Correct Option: D
Explanation:
Option $(D)$ is correct.
Oxide used to treat indigestion and relieve pain are magnesium hydroxide and magnesium oxide. Heartburn and acid indigestion are caused by excess acid in the stomach. Magnesium oxide and hydroxide treats these stomach problems by neutralizing the acid in the stomach. 

The powder of zinc phosphate cement contain zinc oxide and:

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

  1. magnesium sulphate

  2. magnesium phosphate

  3. magnesium oxalate

  4. magnesium oxide

Show answer
Correct Option: D
Explanation:
Option $(D)$ is correct.
The powder of zinc phosphate cement contains zinc oxide and magnesium oxide. It is used for dentistry, cementation of inlays, crowns, bridges etc.

The compounds of alkaline earth metals ($Mg$) have following magnetic nature:

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

  1. diamagnetic

  2. anti ferromagnetic

  3. ferromagnetic

  4. paramagnetic

Show answer
Correct Option: A
Explanation:

The compounds of alkaline earth metal are diamagnetic because they don't have any unpaired electrons. Their electronic configuration is $np^6ns^2$.

Which of the following(s) is/are correct for magnesium and zinc?

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

  1. $MgO$ and $ZnO$ are amphoteric

  2. $MgCO _3$ and $ZnCO _3 $ both on heating give corresponding oxides

  3. Both are used as electrodes

  4. Both are used to prevent corrosion

Show answer
Correct Option: B,C,D
Explanation:
Option $(B)\ ,(C),\ (D)$ are correct. They all are facts.
$MgO$ is basic while $ZnO$ is amphoteric in nature.

Magnesium is an important component of which biomolecule occuring extensively in living world?

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

  1. Haemoglobin

  2. ATP

  3. Chlorophyll

  4. Vitamin B

Show answer
Correct Option: C
Explanation:

Hemoglobin contains iron, vitamin $B$, cobalt. Chlorophyll contains magnesium. ATP is adenosine triphosphate contains phosphorous.

Which ionisation energy of alkaline earth metal is less than that of alkali metals?

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

  1. Third

  2. Second

  3. First

  4. Fourth

Show answer
Correct Option: B
Explanation:
The second ionisation energy of alkaline earth metal is less than that of alkali earth metals.
The 2nd electron in case of alkali metal is to be removed from a cation (unipostive ion) which has already acquired a noble gas configuration whereas, in case of alkaline earth metals, the second electron is to be removed from a cation which is yet to acquire the stable noble gas configuration. Therefore, removal of 2nd electron in case of alkaline earth metals requires much less energy than that in the case of alkali metals.

Hence, the correct option is $B$

Sorel cement is the mixture of:

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

  1. $CaCO _3+H _2O$

  2. $MgCl _2+MgO$

  3. $BaSO _4+CO _2$

  4. $MgO+Na _2HPO _4$

Show answer
Correct Option: B
Explanation:

Sorel cement is a mixture of magnesium chloride and magnesium oxide.

$5MgO+MgCl _2+13H _2O \rightarrow MgCl _2.5Mg(OH) _2.H _2O$
$3MgO+MgCl _2+11H _2O \rightarrow MgCl _2.3Mg(OH) _2.H _2O$

The formula for the most abundant mineral in phosphate rock is: 

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

  1. $Ca _5(PO _4) _3F$

  2. $Ca _5(PO _4) _2F _4$

  3. $Ca _4(PO _4) _2F _2$

  4. $Ca _6(PO _4) _3F _3$

Show answer
Correct Option: A
Explanation:

Most abundant mineral of phosphate rock is Fluorapetite, which has the formula of $Ca _5(PO _4) _3F$.

The most abundant mineral in Phosphate rock is: 

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

  1. Flourspar

  2. Phosphane

  3. Flourapetite

  4. Phosphide

Show answer
Correct Option: C
Explanation:

Most abundant mineral of phosphate rock is Fluorapetite, which has the formula of $Ca _5(PO _4) _3F$.