Respuesta :
Answer : The correct option is, (D) 89.39 KJ/mole
Explanation :
First we have to calculate the moles of HCl and NaOH.
[tex]\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole[/tex]
[tex]\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole[/tex]
The balanced chemical reaction will be,
[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex]
From the balanced reaction we conclude that,
As, 1 mole of HCl neutralizes by 1 mole of NaOH
So, 0.3562 mole of HCl neutralizes by 0.3562 mole of NaOH
Thus, the number of neutralized moles = 0.3562 mole
Now we have to calculate the mass of water.
As we know that the density of water is 1 g/ml. So, the mass of water will be:
The volume of water = [tex]137ml+137ml=274ml[/tex]
[tex]\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 274ml=274g[/tex]
Now we have to calculate the heat absorbed during the reaction.
[tex]q=m\times c\times (T_{final}-T_{initial})[/tex]
where,
q = heat absorbed = ?
[tex]c[/tex] = specific heat of water = [tex]4.18J/g^oC[/tex]
m = mass of water = 274 g
[tex]T_{final}[/tex] = final temperature of water = 325.8 K
[tex]T_{initial}[/tex] = initial temperature of metal = 298 K
Now put all the given values in the above formula, we get:
[tex]q=274g\times 4.18J/g^oC\times (325.8-298)K[/tex]
[tex]q=31839.896J=31.84KJ[/tex]
Thus, the heat released during the neutralization = -31.84 KJ
Now we have to calculate the enthalpy of neutralization.
[tex]\Delta H=\frac{q}{n}[/tex]
where,
[tex]\Delta H[/tex] = enthalpy of neutralization = ?
q = heat released = -31.84 KJ
n = number of moles used in neutralization = 0.3562 mole
[tex]\Delta H=\frac{-31.84KJ}{0.3562mole}=-89.39KJ/mole[/tex]
The negative sign indicate the heat released during the reaction.
Therefore, the enthalpy of neutralization is, 89.39 KJ/mole
