Tag: reaction of metals

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Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

Which one of these gas is released when Na reacts with cold water?

  1. $H _2$
  2. $Cl _2$
  3. $O _2$
  4. $H _2O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reaction of 'Na' with cold water. 

$ 2Na+H _{2}O\rightarrow Na _{2}O+H _{2} \uparrow $
               The reaction stops with forming $ Na _{2}O $ . Because, we used cold water. The reaction doesnt continue to form NaOH.

Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

Which of the following is added to remove permanent hardness of water?

  1. baking soda

  2. blue vitriol

  3. washing soda

  4. milk of magnesia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

By adding Na$ _{2} $Co$ _{3} $, all the Ca$ ^{+2} $ and and Mg$ ^{+2} $ ions which causes permanent hardness are replaced by Na$ ^{+} $, which doesn't cause hardness.

Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

Sodium hydroxide in water gives

  1. yellow color solution.

  2. green color solution.

  3. colorless solution.

  4. light pink solution.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Sodium hydroxide in water gives colorless solution.
Sodium hydroxide is colourless. In water, it dissociates into sodium ions and chloride ions. These ions are also colourless.
$\displaystyle NaOH (aq)   \xrightarrow{H _2O} Na^+ (aq) + OH^- (aq)$

Multiple choice chemistry metals reaction of metals reactions of metals chemical properties of metals

Potassium's reaction with water produces hydrogen gas of 

  1. bluish pink.

  2. greenish blue.

  3. orange.

  4. light pink.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Potassium's reaction with water produces hydrogen gas of bluish pink.
Potassium reacts with cold water and gives potassium hydroxide and hydrogen gas.
$\displaystyle 2K + 2H _2O \rightarrow 2KOH + H _2$
The reaction is exothermic and the resulting solution is basic.
The reaction is so vigorous that the evolved hydrogen catches fire spontaneously.