Tag: chemical properties of metals

Questions Related to chemical properties of metals

The reactivity series is a list of metals arranged in the order of their _______ activities.

  1. decreasing

  2. Increasing

  3. chemical

  4. physical


Correct Option: A
Explanation:

The reactivity series is a series of metals, arranged in order of reactivity from highest to lowest. It is used to determine the products of single displacement reactions, whereby metal A will replace another metal B in a solution if A is higher in the series.

Sodium reacts with zinc chloride to form -

  1. Sodium chloride

  2. Zinc metal

  3. Both (a) and (b)

  4. None


Correct Option: C
Explanation:

$2Na + ZnCl _2 \rightarrow 2NaCl + Zn$

Here, more reactive metal sodium is displacing less reactive metal zinc from its compound.

The metallic oxide/s which cannot be reduced by normal reducing agents.

  1. Magnesium oxide

  2. Copper $(II)$ oxide

  3. Zinc oxide

  4. Iron $(III)$ oxide


Correct Option: A
Explanation:

Among given metal oxides, magnesium have very low reduction potential so it can not be reduced by normal reducing agents.

Which is the least reactive metal in the reactive series?

  1. Copper

  2. Mercury

  3. Silver

  4. Gold


Correct Option: D
Explanation:

Gold is least reactive metal because of higher standard reduction potential value.

Name a metal from the activity series which displaces hydrogen from steam?

  1. Zinc

  2. Iron

  3. Copper

  4. Magnesium


Correct Option: D
Explanation:

Magnesium can displace hydrogen from steam. Mg is better reducing agent than hydrogen as Mg les above hydrogen in the reactivity series.
Hence, the tendency for the reaction $\displaystyle Mg \rightarrow Mg^{2+} + 2e^-$ is greater than the tendency for the reaction $\displaystyle 2H^+ + 2e^- \rightarrow H _2$. Hence, Mg will be oxidised and $\displaystyle H^+$ will be reduced.

Metals above hydrogen in activity series :

  1. react with base to liberate hydrogen ions

  2. react with acids to liberate hydrogen gas

  3. react with water at ordinary temperature

  4. none of the above


Correct Option: B
Explanation:

The activity series is a listing of the metals in decreasing order of their reactivity with hydrogen ion sources such as water and acids. In the reaction with hydrogen ion source the metal is oxidized to a metal ion and the hydrogen is reduced to hydrogen gas. They are also good reducing agents and poor oxidizing agents.

A small piece of silver is placed in a solution containing both magnesium nitrate and copper (II) nitrate. Which one of the following occurs?

  1. No reaction takes place

  2. The silver dissolves and only copper is precipitated

  3. The silver dissolved and only magnesium is precipitated

  4. A mixture of magnesium and copper forms on the silver


Correct Option: A
Explanation:

Silver is the metal which is present at the bottom of reactivity series below $Mg$ and $Cu$ metals so it cannot displace these metals from its solution. In this case, no reaction takes place by this piece of silver.

In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of:

  1. $Cl _2$

  2. $H _2$

  3. $N _2$

  4. $O _2$


Correct Option: C
Explanation:

In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of $N _2$ to prevent from being rancid or oxidised. 
Nitrogen is added to the potato chip packet to add strength to the packaging. Normally aluminium cans are used for packaging beverages, these beverages are carbonated drinks and the carbon dioxide present in them provides the internal pressure in the can and thus gives internal strength to the aluminium can. But in non-carbonated drinks, there is no carbon dioxide present and so Nitrogen is added to it to give the required strength to the packing.

Which of the following metal will not displace hydrogen gas from dilute $H _2SO _4$?

  1. Zinc

  2. Iron

  3. Copper

  4. Aluminium


Correct Option: C
Explanation:

Since, the copper is present below the hydrogen in the activity series it cannot displace hydrogen from the sulphuric acid.

Two metals lighter than water are:

  1. $Li,\ Na$

  2. $Al,\ Mn$

  3. $Pb,\ Mg$

  4. $Co,\ Mn$


Correct Option: A
Explanation:

$Li$ and $Na$ both metals belong to the alkali metals.


They are soft metals and have low ionization enthalpy,


Lithium is lighest elemental metal nearly half as dense as water, so if floats on the surface and ultimately diasppears, giving off hydrogen gas and forming a colourless solution of lothium hydroxide.

Sodium is also lighter than water nad have a density of $0.971 g/cm^3$,

hence, $Li$ and $Na$ both metals are lighter than water.


Hence, the correct option is $\text{A}$