Tag: reaction of metals

Questions Related to reaction of metals

What does the pop sound indicate when sodium reacts with cold water?

  1. Release of oxygen

  2. Release of carbon dioxide

  3. Both A and B

  4. Release of hydrogen


Correct Option: D
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. To test for the release of hydrogen gas, place a lighted splint over the reacting metal - if it "pops" then hydrogen is present.

Which of the following reacts with cold water vigorously?

  1. Carbon

  2. Sodium

  3. Magnesium

  4. Sulphur


Correct Option: B
Explanation:

Sodium is a light and soft metal that reacts vigorously with cold water. Sodium when dropped in cold water forms a ball and moves on the surface of cold water with sodium hydroxide formation accompanied with the release of hydrogen gas.
$2Na+2H _2O \rightarrow 2NaOH +H _2$

Which of the following metal reacts with steam but not hot/cold water?

  1. Al

  2. Zn

  3. Fe

  4. All of above


Correct Option: D
Explanation:

Metals like aluminium, zinc, iron do not react with hot/cold water ; they react only with steam to form a metal oxide and hydrogen .

The metal that reacts with cold water is :

  1. mercury

  2. sodium

  3. zinc

  4. tungsten


Correct Option: B
Explanation:

Sodium is highly reactive with cold water forming hydroxides and hydrogen gas. Hence, sodium is always stored under kerosene. Mercury, zinc and tungsten are found in the reactivity series at the bottom and are not highly reactive compared to sodium.

Metals combine with oxygen to form _________ oxides.

  1. basic

  2. acidic

  3. neutral

  4. both A and B


Correct Option: A
Explanation:

Metals form basic or amphoteric oxides while non metals form acidic oxides.

Aluminium does not oxidize readily in air because :

  1. it is high in the electrochemical series

  2. it is low in the electrochemical series

  3. the metal does not combine with oxygen

  4. the metal is covered with a layer of oxide which does not rub off


Correct Option: D
Explanation:

Aluminium is soft silvery metal, yet the surface gets tarnished due to the formation of film of its oxide $Al _2O _3$.
When aluminium is exposed to moist air a thin film of  oxide layer which is thin, hard and adhering.
$4Al+3O _2 \rightarrow 2Al _2O _3$

Metal reacts with oxygen to form _________ .

  1. Acid

  2. Base

  3. Metallic oxide

  4. Non-metallic oxide


Correct Option: C
Explanation:

Metal + Oxygen $\rightarrow$ Metallic oxide

Example: 
      $2Mg(s) + O _2(g) \rightarrow 2MgO(s)$ 

In which molecules s-p overlapping occurs?

  1. $CH _{4}$

  2. $NH _{3}$

  3. $H _{2}O$

  4. None of these


Correct Option: B
Explanation:

s-p overlapping one such type of overlapping. Here there is a overlapping between the s- and p- orbital's of the molecules. This type of overlapping is generally seen in the NH3 molecules. This formed by overlapping between 3 orbital's of hydrogen and 3 of nitrogen

Among the metals, the one that cannot be obtained by the reduction of its metal oxide.

  1. $Cr$

  2. $Fe$

  3. $Mn$

  4. $Mg$


Correct Option: A
Explanation:

Actually the oxides of metals like Zn,Pb and other metals which are not very reactive can be reduced by Carbon. However oxides of very reactive metals (eg Aluminium,Chromium) can't be reduced by Carbon . Since they are very reactive they react with carbon to form their carbides hence are not effective in reduction.

Metals such as lead, copper, silver and gold do not react with water at all.

  1. Statement is False

  2. Statement is True

  3. Lead reacts but copper, silver, and gold do not

  4. Copper reacts but lead, silver and gold do not.


Correct Option: B