Question

Why is citric acid added to soft drinks?

Answer 1

The citric acid reacts with the baking soda to make the soft drink "bubbly", and it also contributes to the taste of the soft drink.

Explanation:

Citric acid is an acid found in citrus fruits such as lemons, limes, grapefruit and oranges.

The sugar provides a sweet taste, and the citric acid provides a sharp, tangy taste to a soft drink.

The baking soda contains carbon dioxide in a combined form, and the citric acid reacts with the baking soda to free the carbon dioxide as a gas.

The carbon dioxide forms the bubbles in the drink.

`3underbrace("NaHCO"_3)_color(red)("baking soda") + underbrace("H"_3"C"_6"H"_5"O"_7)_color(red)("citric acid") → underbrace("Na"_3"C"_6"H"_5"O"_7)_color(red)("sodium citrate") + 3underbrace("H"_2"O")_color(red)("water") + underbrace("3CO"_2)_color(red)("carbon dioxide")`

You might also notice a slightly salty taste caused by formation of the sodium citrate.