Tag: ionisation of weak acids and weak bases

Questions Related to ionisation of weak acids and weak bases

Generally speaking, how can you determine the charge of an ion formed by a representative element?

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. The charge of the ion formed is related to the element's group number.

  2. The charge of the ion is related to the element's period number.

  3. An ion's charge is always 1/2 the atomic number.

  4. The charge of the ion is the number of valence electrons minus the number of core electrons.

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Correct Option: A
Explanation:

Representative elements : s-block and p-block elements are representative elements.
The charge of the ion formed is related to the element's group number.
For example:
As Group-1 elements have +1 charge.
As Group-2 elements have +2 charge.

$\frac { N } { 10 }$ acetic acid was titrated with $\frac { N } { 10 }$ NaOH.When $25 \% , 50 \%$ and $75$$\%$ of titration is over then the pH of the solution will be $: \left[ \mathrm { K } _ { a } = 10 ^ { - 5 } \right]$

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. $5 + \log 1 / 3,5,5 + \log 3$

  2. $5 + \log 3,4,5 + \log 1 / 3$

  3. $5 - \log 1 / 3,5,5 - \log 3$

  4. $5 - \log 1 / 3,4,5 + \log 1 / 3$

Show answer
Correct Option: A
Explanation:
t     CH_3COOH         NaOH          CH_3COO^-Na^+

0       0.1                      0.1
    
25%   0.1-0.025        0.1-0.025         0.025

50%   0.1-0.050        0.1-0.050         0.050

75%   0.1-0.075         0.1-0.075          0.075

$pH=- \log K _a+\log \dfrac{[salt]}{[acid]}$

t= 25%

$pH=5+\log \dfrac{0.025} {0.075}$

$pH=5+\log \dfrac{1} {3}$

t= 50%

$pH=5+\log \dfrac{0.050} {0.050}$

$pH=5+\log 1=5$

t= 75%

$pH=5+\log \dfrac{0.075} {0.025}$

$pH=5+\log 3$

Two electrolytic cells containing molten solutions of Nickel chloride and Aluminium chloride are connected in series. If same amount of electric current is passed through them, what will be the weight of Nickel obtained when $18gm$ of Aluminium is obtained? $\left( Al-27gm/mole,Ni-58.5gm/{ mole }^{ -1 } \right) $

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. $58.5gm$

  2. $117gm$

  3. $29.25gm$

  4. $5.85gm$

Show answer
Correct Option: A
Explanation:
$By Faraday's Second Law$
$\frac{(m)N _{i}}{(m) _{N _{A1}}}=\frac{(E)N _{i}}{(E) _{N _{A1}}}$
$\frac{(m)N _{i}}{18}=\frac{58.5\times 2}{3\times 27}$
$(m){N _{i}}=58.5 g$

100 mL of 1 M HCl is mixed with 50 mL of 2 M HCl. Hence, $[H 3O^+]$ is _______.

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. 1.00 M

  2. 1.50 M

  3. 1.33 M

  4. 3.00 M

Show answer
Correct Option: C
Explanation:

FInal concentration of $H _3O^+,[H _3O^+]$=$\cfrac {V _1S _1+V _2S _2}{V _1+V _2}$

                                                                 =$\cfrac {100 \times 1+ 50 \times 2}{100 + 50}$
                                                                 =$ 1.33M$ .

What concentrations of $CH _3COOH$ and $CH _3COONa$ are needed to prepare a 0.10M buffer at pH 5.0?

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. 0.09

  2. 0.06

  3. 0.6

  4. 0.9

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Correct Option: B

Solubility of $MX _{ 2 }$ type electrolytes is $0.5\times 10^{ -4 } mol/L$, Then find out ${ K } _{ sp }$ of electrolytes.

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. $5\times 10^{ -12 }$

  2. $25\times 10^{ -10 }$

  3. $1\times 10^{ -13 }$

  4. $5\times 10^{ -13 }$

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Correct Option: D

Diamagnetism is exhibited by_____

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. cobalt

  2. water

  3. oxygen

  4. iron

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Correct Option: B
Explanation:

Diamagnetic materials, like water, or water-based materials, have a relative magnetic permeability that is less than or equal to 1, and therefore a magnetic susceptibility less than or equal to 0. Diamagnetic materials are repelled by magnetic fields.

$H _2O \longrightarrow H^+ + OH^-$
The above reaction is dissociation or ionization?

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. Dissociation

  2. Ionization

  3. Both dissociation and ionization together

  4. None of these

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Correct Option: B
Explanation:

Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions. It does not split like in dissociation reaction.

Therefore, $ { H } _{ 2 }O\rightarrow \quad { H }^{ + }+{ { OH }^{ - } } $ is an ionization reaction. 

Which will not affect the degree of ionisation?

chemistry ionic equilibrium introduction to ionic equilibria in solution ionic equilibrium in solution ionisation of weak acids and weak bases

  1. Temperature

  2. Concentration

  3. Type of solvent

  4. Current

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Correct Option: D
Explanation:

Degree of ionisation changes according to the temperature, concentration and the type of electrolyte like strong electrolyte or weak electrolyte, it does not varies with current.

The addition of $HCl$ will not suppress the ionisation of:

chemistry further aspects of equilibria dissociation constants ionisation of weak acids and weak bases ionization constants of weak acids and weak bases

  1. Acetic acid

  2. Sulphuric acid

  3. ${H} _{2}S$

  4. Benzoic acid

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Correct Option: B
Explanation:

The addition of $HCl$ will not suppress the ionisation of $H _2SO _4$ because $H _2SO _4$ is stronger acid than $HCl$.