Question

All alkalis are bases but all Bases are not alkali.
A.) True
B.) False

Answer 1

Hint: An Arrhenius Base is any species that increases the concentration of $\left( O{{H}^{-}} \right)$ in aqueous solution whereas an Alkali is a basic hydroxide or ionic salt which is soluble in water, which produces hydroxide ions $\left( O{{H}^{-}} \right)$$\left( aq \right)$ when dissolved in water.

Complete Solution :
A substance that neutralizes an acid is generally called a base and the basic substances that are soluble in water and alkali and the properties of alkalis are due to these hydroxide ions$\left( O{{H}^{-}} \right)$. However, all bases are not soluble in water. Let us take an Example:
Copper (II) Oxide$\left( CuO \right)$ which is a basic metallic oxide and can neutralize acids but it cannot get dissolved in water and, thus, cannot be called an Alkali.
- Thus, conclusively it can be said that all alkalis are bases but all bases are not alkali. Henceforth the given statement is true and the correct option would be (A) True.
So, the correct answer is “Option A”.

Note: Though Bases are used to neutralize acids but it is to be kept in mind that Just like concentrated acids, concentrated alkalis are also corrosive and are just as dangerous as concentrated acids, sometimes more. Though they are soapy to touch but they can attack metals and destroy skin if spilled, so their containers are labeled with a warning symbol ‘Concentrated alkalis’ .Thus it is always advised to use Concentrated Alkalis with utmost Precautionary care.