Q. The standard enthalpy of neutralization of strong acid and strong base is $-57.3$ $kJ$ $\text{equiv}^{- 1} .$ If the enthalpy of neutralization of the first proton of aqueous $H_{2}S$ is $-33.7$ $kJmol^{- 1}$ then the $\left(\left(\text{pK}\right)_{\text{a}}\right)_{1}$ of $H_{2}S$ is

NTA AbhyasNTA Abhyas 2022 Report Error

A

$\left(\frac{23.6 \times 1 0^{3} - T \Delta S ^\circ }{2.303 R T}\right)$

B

$\left(\frac{2.303 R T}{23.6 - T \Delta S ^\circ }\right)$

C

$\left(\frac{T \Delta S ^\circ - 23.6}{R T}\right)$

D

$2.303\left(\frac{T \Delta S ^\circ - 23.6}{R T}\right)$

Solution:

$H_{2}S\rightleftharpoonsH^{+}+HS^{-}$
$\Delta H_{i o n}=23.6$ $kJ$
$\therefore \Delta G^\circ =23.6\times 10^{3}-T\Delta S^\circ =-2.303RTlogK_{a_{1}}$
$\therefore P_{K a_{1}}=\frac{23.6 \times 1 0^{3} - T \Delta S ^\circ }{2.303 R T}$

Questions from NTA Abhyas 2022

1. An alkene $\left(\right.A\left.\right)$ on ozonolysis gives a mixture of two carbonyl compounds. Mixture on Clemmensen reduction gives just one alkane $\left(\right.B\left.\right)$ . $\left(\right.B\left.\right)$ is the lowest alkane which in pure form can not be prepared by standard Wurtz method. $\left(\right.A\left.\right)$ is

2. A cation is in the centre touches three anions. Assume that the anions also touch each other. The limiting radius ratio, $r^{+}/r^{-}$ is

3. Blue colour of alkali and alkaline earth metals in liquid $NH_{3}$ is due to

4. Which of the following oxides is strongly basic?

5. In a $10litre$ box $2.5mole$ hydroiodic acid is taken. After equilibrium $2HI\rightleftharpoonsH_{2}+I_{2}$ the concentration of $HI$ is found to be $0.1 \, \text{mol} \, \text{L}^{- 1}$ . The concentration of $\left[H_{2}\right]$ at equilibrium in $molL^{- 1}$ , is

Chemistry Most Viewed Questions

1. If for a certain reaction $\Delta_{r}H$ is $30\, kJ\, mol^{-1}$ at $450 \,K$, the value of $\Delta_{r}S$ (in $JK^{-1}\, mol^{-1})$ for which the same reaction will be spontaneous at the same temperature is

NEET 2020

2. If $8\,g$ of a non-electrolyte solute is dissolved in $114\, g$ of n-octane to reduce its vapour pressure to $80\%$, the molar mass (in $g \,mol^{-1})$ of the solute is [Given that molar mass of n-octane is $114 \,g\, mol^{-1}]$

NEET 2020 Solutions

3. An organic compound contains $78 \%$ (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of $C$ is $12, H$ is $1$]

NEET 2021 Some Basic Concepts of Chemistry

4. At standard conditions, if the change in the enthalpy for the following reaction is $-109 \,kJ\, mol^{-1}$ $H_{2(g)}+Br_{2(g)} \to 2HBr_{(g)}$ Given that bond energy of $H_{2}$ and $Br_{2}$ is $435\,KJ\,mol^{-1}$ and $192\,KJ\,mol^{-1}$ , respectively, what is the bond energy (in $KJ \,mol^{-1})$ of $HBr$ ?

NEET 2020

5. The density of 2 M aqueous solution of NaOH is 1.28 g/cm$^3$. The molality of the solution is
[Given that molecular mass of NaOH = 40 g mol$^{-1}$]

NEET 2019 Some Basic Concepts of Chemistry

Latest Updates