Question

Equal volumes of ${\text{1M }}HCl$ and $1{\text{M }}{H_2}S{O_4}$ are neutralized by dilute $NaOH$ solution liberating $x\,{\text{cal}}$ and $y\,{\text{cal}}$ heat.
Which of the following is correct?
A.$x = y$
B.$x = 0.5y$
C.$x = 0.4y$
D.None of the above

Answer 1

To answer this question, you should recall the concept of acid-base neutralization reaction and heat of neutralization. The heat released depends on the number of hydrogen ions neutralized by one molecule of base.

Complete Step by step solution:
In a neutralization reaction, there is a combination of ${H^ + }$ ions and $O{H^-}$ ions which form water.
Reactions involved are:
$HCl + NaOH \to NaCl + {H_2}O,\Delta {H_1} = xkcal$
${H_2}S{O_4} + 2NaOH \to N{a_2}S{O_4} + 2{H_{2}}O,\Delta {H_1} = ykcal$
Acid-base neutralization reaction for $HCl$ is represented as:
${H^ + } + O{H^ - } \to {H_2}O,\Delta {H_1} = x kcal$
Acid-base neutralization reaction for ${H_2}S{O_4}$ ​ is represented as:
$2{H^ + } + 2O{H^ - } \to 2{H_2}O,\Delta {H_1} = y kcal$
Since reaction (ii) is twice of reaction (i), so the relation between enthalpies will be
thus
$2x = y$
$\Rightarrow \;x = 0.5y$.

Hence, the correct answer to this question is Option B.

Note: The different types of salts resulting from neutralization reaction are: based on their constituents
1. Acidic salt: The salt resulting from partial neutralization of a polyprotic acid is known as an acidic salt. These salts have ionizable ${H^ + }$ ions along with another cation. Examples of these types of salts are etc.
2. Basic or Alkali Salt: This type of salt is formed by the partial neutralization of a strong base by a weak acid is known as a basic salt. These salts hydrolysis to form a basic solution. Example of these types of salts is: White lead $(2PbC{O_3}.Pb{\left( {OH} \right)_2}).$
3. Double salt: These types of salts contain more than one cation or anion is known as double salt. They are obtained by the combination of two different salts crystallized in the same ionic lattice. Example of these types of salts is Potassium sodium tartrate $(KNa{C_4}{H_4}{O_6}.4{H_2}O)$ which is also known as Rochelle salt.
4. Mixed Salts: These types of salts are made up of a fixed proportion of two salts, often sharing either a common cation or common anion is known as mixed salt.