Question

Assertion: Metals placed in group 1 are known as alkali metals.

Reason: These metals dissolve in water to form solution of Alkaline nature.

Mark the correct choice as,

• A. Both assertion and reason are true and the reason is the correct explanation of assertion.
• B. Both assertion and reason are true but the reason is not the correct explanation of assertion.
• C. Assertion is true but the reason is false.
• D. Both assertion and reason are false.

Answer 1

The correct option is A

Both assertion and reason are true and the reason is the correct explanation of assertion.

Explanation for Assertion statement:

1. There are a total of 18 horizontal columns in the modern periodic table, they are called groups.
2. Metals from group 1 are known as alkali metals.

Explanation for reason statement:

1. The elements Lithium, Sodium, Potassium, Rubidium, Caesium and Francium occupy group 1 of the periodic table and are called Alkali metals.
2. They have the tendency to lose an electron to complete their octet so they are strongly electropositive and very reactive in nature,
3. They are called ‘alkali’ metals because they violently react with water to form strong alkaline hydroxides (basic in nature) and hydrogen gas is released.

$2M\left(s\right)+2H_{2}O\left(l\right)\to 2MOH\left(aq\right)+H_2\left(g\right)$

Hence, A) Both assertion and reason are true, reason is the correct explanation of assertion.