Question

X reacts with calcium carbonate giving $C{O_2}$ and ${H_2}O$ and turns methyl orange to:
(A) Yellow
(B) Red
(C) No colour change
(D) Pink

Answer 1

Methyl orange is an indicator used to find out the nature whether the compound given is acid or base. There are various other indicators like Phenolphthalein, Turmeric, litmus paper, natural litmus and many more.

Complete answer:
First we start with thinking about which compound is the $X$ ,
So, as given $X$ reacts with calcium carbonate giving $C{O_2}$ and ${H_2}O$
We have to know what happened when any compounds reacts with carbonates:
Reaction of carbonates with acid:
When acids react with carbonates, they form salt, carbon dioxide and water.
So, $X$ will be an acid.
As acid reacts with carbonates to form carbon dioxide and water.
Now, we talk about the properties of the methyl orange:
Methyl orange is a pH indicator which shows red colour with acidic medium and yellow colour with basic medium.
So, when the acid which reacts with calcium carbonates to form carbon dioxide and water turns methyl orange into red.
Hence, the correct option is (B) Red.

Additional information:
There are different indicators other than methyl orange. Phenolphthalein is one of them. It turns the solution colourless in acidic solution and pink in basic solution.
There are also papers which are used for the acidic and basic nature like blue litmus and red litmus paper. Blue litmus paper turns red with acid and remains unchanged with base. Red litmus paper turns blue with base and remains unchanged with acid.

Note:
pH is a scale used to determine the acidic or basic nature of the given aqueous solution. It ranges from one to fourteen, and the pH less than seven is marked as acid and more than seven is marked as base.