Correct Answer - Option 4 : Hydrogen
The correct answer is Hydrogen.
- The common element for all acids is hydrogen.
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Hydrogen is the element that is common to all acids.
- When an acid is dissolved in water, it gives out H+ ions which are protons.
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An acid is a substance that donates hydrogen ions.
- Because of this, when an acid is dissolved in water, the balance between hydrogen ions and hydroxide ions is shifted.
- Now there are more hydrogen ions than hydroxide ions in the solution.
- A substance will be known as an acid if it gives out positive hydrogen ions, that is, H+ ions when dissolved in water.
- An acidic compound donates a proton.
- The acid is regarded as stable if and only if its conjugate base is also stable.
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A base is a substance that accepts hydrogen ions.
- When a base is dissolved in water, the balance between hydrogen ions and hydroxide ions shifts the opposite way.
- Because the base "soaks up" hydrogen ions, the result is a solution with more hydroxide ions than hydrogen ions.
- This kind of solution is alkaline.
