Question

The more commonly used baking powder contains about $30\% {\text{ }}NaHC{O_3}$, $20\% {\text{ NaAl}}\left( {S{O_4}} \right)$, $10\% {\text{ }}Ca{({H_2}P{O_4})_2}$ and $40\% {\text{ }}starch$ which of the following statements $is/are$ correct?
A. $Ca{\left( {{H_2}P{O_4}} \right)_2}$ is acidic and when moistened it reacts with $NaHC{O_3}$ evolving $C{O_2}$ gas.
B. ${\text{NaAl}}\left( {S{O_4}} \right)$ slows down the decomposition reaction of $NaHC{O_3}$ so that $C{O_2}$ is evolved more slowly.
C. ${\text{NaAl}}\left( {S{O_4}} \right)$ is acidic and when moisturized it reacts with $NaHC{O_3}$ evolving $C{O_2}$.
D. Both $\left( a \right){\text{ and }}\left( b \right)$

Answer 1

We first should have an idea about baking powder. We would discover the nature of dihydrogen phosphate ions about its acidic or basic. Then we would find out the work of $C{O_2}$. Later, we should also know the nature of reactions that took place.

Complete step by step solution:
Baking Powder is a mixture of carbonate or bicarbonate and a weak acid. It is used to increase the volume of baked things and smoothen and lighten the texture of baked goods.
Here, the dihydrogen phosphate ion works as an acid. Work of an acid is to donate a proton. So when the liquid ingredients of a dough are added, the ion will give a proton to the bicarbonate ion. This will result in formation of carbonic acid.
Now, the carbonic acid will decompose itself into carbon dioxide and water. The $C{O_2}$ will try to leave and which will lighten the texture of dough and will increase its volume.
A decomposition reaction will take place of $NaHC{O_3}$ which is slowed down by ${\text{NaAl}}\left( {S{O_4}} \right)$. It results in slow evolution of the $C{O_2}$.
Another reaction which takes place in the process is acid base reaction which gives water and $C{O_2}$. It is often formed in the form of bubbles. So we always need to be careful while stirring.

Hence, Option D is correct.

Note: Baking powder is commonly used in every household. It has a bitter taste. It was discovered by Alfred Bird in $1843$. It is a replacement for the yeast which was used for fermentation. It almost provides $5Kcal./cup$.