Question

The given reaction releases which of the following gas?
$ HCl + NaHC{O_3} \to $
A. $ {O_2} $
B. $ C{O_2} $
C. $ {H_2} $
D. $ C{l_2} $

Answer 1

Hint: The given reaction includes two types of compounds, an acid and a base. Here $ HCl $ is an acid and $ NaHC{O_3} $ acts as a base in solution. The type of reaction when an acid and a base react with each other is known as neutralization.

Complete step by step answer:
In the given reaction, we can see that $ HCl $ is reacting with $ NaHC{O_3} $ . As we know that this type of reaction is known as neutralization reaction and similarly in this scenario also we will get salt and water as our products. First let’s analyze the reactants. $ HCl $ is itself a very strong acid with a pH value of $ 3 $ . Whereas $ NaHC{O_3} $ is a basic salt which when dissolved in water acts as a weak/mild base.
When $ HCl $ and $ NaHC{O_3} $ react with each other, $ HCl $ dissociates to give a high number of $ {H^ + } $ ions (due to its strong acidic nature). While, $ NaHC{O_3} $ dissociates to produce $ HCO_3^ - $ ions instead of $ O{H^ - } $ ions (because of its weak basic nature it is unable to produce much $ O{H^ - } $ ions on dissociation but is able to give $ HCO_3^ - $ ions in abundant).
The dissociation reaction looks like this-
$ HCl \to {H^ + } + C{l^ - } $
$ NaHC{O_3} \to N{a^ + } + HCO_3^ - $
As we can see when these two dissociates, they too give out salt along with water but in this case an additional product is produced. When these two acid and base dissociates in aqueous medium the $ {H^ + } $ from $ HCl $ reacts with $ HCO_3^ - $ from $ NaHC{O_3} $ and hence forms $ {H_2}C{O_3} $ (Carbolic Acid). On the other hand the $ N{a^ + } $ from $ NaHC{O_3} $ reacts with $ C{l^ - } $ from the $ HCl $ and hence forms the most common salt $ NaCl $ (Rock Salt). So now we have two products from the above reaction which are $ NaCl $ and $ {H_2}C{O_3} $ . $ {H_2}C{O_3} $ being highly unstable decomposes to give water $ ({H_2}O) $ and only gas $ C{O_2} $ (carbon dioxide).
The reaction looks like this:
$ HCl + NaHC{O_3} \to NaCl + {H_2}C{O_3} $
$ HCl + NaHC{O_3} \to NaCl + {H_2}O + C{O_2} \uparrow $
Thus from the chemical equation we can see that the reaction of $ HCl $ and $ NaHC{O_3} $ gives out only one gas which is $ C{O_2} $ along with the usual products $ NaCl $ and $ {H_2}O $ .

So the correct option is option B.

Note: Carbolic Acid is highly susceptible to decomposition in presence of light. Hence it is stored in dark colored jars or kept in dark rooms thus reducing the chances for decomposition. Carbolic acid is also used in keeping away snakes as they are vulnerable to it.