Tag: reaction of metals

Questions Related to reaction of metals

A metal which reacts with cold water vigorously producing hydrogen is:

  1. zinc

  2. hydrogen

  3. sodium

  4. mercury


Correct Option: C
Explanation:

All the alkali metals react vigorously with cold water. In each reaction, hydrogen gas is given off and the metal hydroxide is produced. The speed and violence of the reaction increases as you go down the group. This shows that the reactivity of thealkali metals increases as you go down group 1. And sodium is a group 1 element.

The correct option is C.

When a metal reacts with water it forms:

  1. alkalies

  2. basic oxide

  3. dilute acid

  4. neutral acid


Correct Option: A
Explanation:

Metals react with water to form alkaline metallic hydroxides.
$Ca+{ H } _{ 2 }O\rightarrow Ca\left( OH \right) _{ 2 }\downarrow +{ H } _{ 2 }\uparrow $

Oxides of which of the following metals is reduced by aluminium powder?

  1. Magnesium

  2. Potassium

  3. Chromium

  4. All of the above


Correct Option: D
Explanation:

All metal oxides loses oxygen and are therefore reduced. Metals always occur in their oxidized state in ores. In order to convert an ore to its elemental state, it is reduced.

Metals react with oxygen to form:

  1. acids

  2. $H^+$ ions

  3. metal oxides

  4. all of the above


Correct Option: C
Explanation:

Metals react with air (oxygen) to form metal oxides. Metals react with oxygen to form basic oxides or amphoteric oxides. 

Metals reacts with water to form $\ {W}$.

  1. $W =$ acidic oxide, carbon dioxide

  2. $W =$ basic oxide, heater

  3. $W =$ metal oxide, hydrogen

  4. $W =$ metal hydroxide, oxygen


Correct Option: C
Explanation:

Metals reacts with water to form a metal hydroxide or metal oxides and hydrogen gas.

What are the products formed when zinc reacts with steam?

  1. Zinc hydroxide and oxygen

  2. Zinc hydroxide and hydrogen

  3. Zinc oxide and oxygen

  4. Zinc oxide and hydrogen


Correct Option: D
Explanation:

When zinc reacts with steam it produces zinc oxide and releases hydrogen gas.

A metal $M$ does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify black coloured product is:

  1. $MgO$

  2. $CuO$

  3. $FeO$

  4. $ZnO$


Correct Option: B
Explanation:

The metal $M$ is copper $(Cu)$ which reacts with oxygen when heated in the air to form black coloured copper(ll) oxide. The reaction can be written as:
$2Cu + O _{2} \rightarrow 2CuO$

$   Mg        +          H _2O   \rightarrow $      

       (cold water)

  1. $MgO + H _2$

  2. $Mg _2O + H _2$

  3. $MgO + H _2O$

  4. The above reaction cannot occur


Correct Option: D
Explanation:

Magnesium and zinc do not react with cold water. They form their respective oxides when reacted with hot water.
$   Mg        +          H _2O         \rightarrow           MgO         +       H _2  $
                            (hot water)

Why is sodium stored in kerosene?

  1. It evaporates

  2. It is highly reactive

  3. It burns

  4. All of above


Correct Option: B,C
Explanation:

Sodium metal is very reactive. It reacts vigorously with oxygen and water. A lot of heat is generated in this reaction. Hence, it is stored in kerosene.

Metals like K, Na react ______ with cold water whereas Ca reacts_____ with cold water.

  1. Violently, less violently

  2. Mildly, violently

  3. Violently, violently

  4. Mildly, does not react


Correct Option: A
Explanation:

Metals like Na, K react violently with cold water to evolve hydrogen gas that catches fire. Ca on other hand, reacts less violently with cold water giving out hydrogen gas which does not catch fire.