For baking a cake, baking powder is used. If baking soda is used instead of baking powder while preparing the cake, what will be the role of the tartaric acid added to baking soda?

Let's start by taking a look at what baking powder and baking soda are made of. Then, we'll look at what happens when they both get hot to determine the proper response to this question.
We are aware that sodium bicarbonate, which has the chemical formula $NaHC{O}_3$, is the sole component of baking soda. Baking powder, on the other hand, combines tartaric acid and sodium bicarbonate.
Sodium bicarbonate breaks down into sodium carbonate and carbon dioxide when heated. This carbon dioxide is what gives cakes their airy and fluffy texture. The following happens as a result:

$2{\mathrm{NaHCO}}_3\stackrel{\text{ heat }}{⟶}{\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}$

Here, we can observe the formation of a potent base, $N{a}_{2}C{O}_3$. The cake has a bitter flavour as a result. However, tartaric acid is included in baking powder to counteract any negative effects sodium carbonate may have on the cake. When tartaric acid and sodium carbonate combine, a salt called sodium tartrate and water are created as a byproduct. Therefore, despite the fact that baking powder contains an acid, doing so will not turn the cake acidic but will instead neutralise the acid and lessen the bitterness that sodium carbonate will otherwise give.

Hence, the correct answer is C.