Tag: chemistry

Quizzes (490) Questions (9892)

Questions Related to chemistry

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

$ MgCl _2 \cdot 6H _2O$ is obtained from carnalite. Which of the following is true?

  1. $ MgCl _2 \cdot 6H _2O$ is left behind in the fused mass
  2. $ MgCl _2 \cdot 6H _2O$ solidifies when fused mass is cooled to 176 deg C
  3. $KCl$ remains in the fused state
  4. Solvent extraction is used to extract $KCl$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carnalite ($ KCl \cdot MgCl _2 \cdot 6H _2O$) is fused and cooled to 176 deg C.  Potassium content solidifies and $ MgCl _2 \cdot 6H _2O$ remains infused state. Fused mass is separated from deposited $KCl$ and is allowed to cool. The remaining $KCl$ is separated by deposition of carnalite crystals, which crystallizes out first.
$ MgCl _2 \cdot 6H _2O$ is left behind in the fused mass.

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

Which of the following is obtained when magnesium chloride reacts with calcium hydroxide?

  1. $Mg(OH) _2$
  2. $Mg$
  3. $Ca$
  4. $CaO$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When magnesium chloride reacts with calcium hydroxide, $Mg(OH) _2$ and $ CaCl _2(aq) $ are obtained.
$MgCl _2(aq) + Ca(OH) _2(aq) \rightarrow  Mg(OH) _2(s) + CaCl _2(aq) $

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

Which the correct chemical reaction among following?

  1. $MgSO _4 \xrightarrow {\Delta} MgO+SO _3$
  2. $Mg _NO _2 \rightarrow Mg _3+N _2$
  3. $MgCO _3 \rightarrow Mg+ CO+CO _2$
  4. $Mg+H _2O \rightarrow Mg(OH) _2+H _2$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Option $(A)$ is correct.

A). $MgSO _4 \xrightarrow {\Delta} MgO+SO _3$
C). $MgCO _3 \rightarrow Mg + CO _2$
D). $Mg+H _2O \rightarrow MgO + H _2$.
Magnesium reacts with water vapor to magnesium hydroxide and hydrogen gas

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

Reaction of magnesium with air is:

  1. endothermic reaction

  2. reversible reaction

  3. exothermic reaction

  4. substitution reaction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Option $(C)$ is correct.

The reaction of magnesium with air is an exothermic reaction as magnesium burns with dazzling brilliance in the air forming white shiny magnesium oxide with the evolution of a lot of heat.
$2Mg + O _2 \rightarrow 2MgO + heat$

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

Oxide used to treat indigestion and relieve pain is:

  1. magnesium oxide

  2. magnesium hydroxide

  3. potassium oxide
  4. both $A$ and $B$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Option $(D)$ is correct.

Oxide used to treat indigestion and relieve pain are magnesium oxide and magnesium hydroxide.
They act as an antacid to relieve indigestion, sour stomach, and heartburn.

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

Which of the following statement is correct?

  1. Magnesium oxide is highly soluble in water

  2. Magnesium oxide is slightly solution in water

  3. Magnesium oxide is insoluble in water

  4. All alkaline earth metal oxides are insoluble in water
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Option $(B)$ is correct.

Magnesium oxide is slightly soluble in water.It is due to an intramolecular force of the magnesium oxide compound. In fact, magnesium oxide is very small, and the attraction forces are very strong to be broke apart when reacted with water.