Home
Class 11
CHEMISTRY
Hydrolysis is an acid-basedreaction of a...

Hydrolysis is an acid-basedreaction of a cation or anion or both ions of a salt with water, Resultan solution of hydrolysis may be acidic, basic or netural. The anion `A^(-)` which is a weakeer base than `OH^(-)` and which his its conjugate acid HA stronger then water but weaker than `H_(3)O` shown the phenomenon of hydrolysis Ex : `CH_(3)COO^(-),CN^(-),NO_(2)^(-)` etc.
The contion `B^(+)` which is a weaker acid than `H_(3)^(+)` which is a weaker acid then `H_(3)^(+)` and which has its conjugate base BOH stronger than water but weak than `OH^(-)` shown the phenmenon of hydrolysis Ex : `NH_(4)^(+)C_(6)H_(5)NH^(+),N_(2)H_(5)^(+)` etc.
The hydrolysis constant of anion and cation are given by
`A^(-)(aq.)+H_(2)O(l)hArrHA(aq.)+OH^(-)(aq)`
`" " K_(h)=(K_(w))/(K_(a))rArr([HA(aq.)][OH^(-)(aq.)])/([A^(-)(aq.)])`
`B^(+)(aq.)+H_(2)O(l)hArrBOH(aq.)+H^(+)(aq.)`
`" " K_(h)=(K_(w))/(K_(b))rArr([BOH(aq.)][H^(+)(aq.)])/([B^(-)(aq.)])`
When pure ammonium chloride is dissolved in pure water, the pH of the resulting not 7. This is because :

A

Ammonium ions accept protons from water molecules leaving fee `OH^(-)` ions in solution

B

ammonium ions donate protons to water molecules froming `H_(3)^(+)` ions in solution

C

Ammonium ions combine with water molecule to give the weak base, ammonium hydroxide

D

chloride ion made the solution acidic

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question regarding why the pH of a solution of ammonium chloride (NH4Cl) in pure water is not equal to 7, we can follow these steps: ### Step-by-Step Solution: 1. **Understanding the Dissociation of Ammonium Chloride:** When ammonium chloride (NH4Cl) is dissolved in water, it dissociates into its constituent ions: \[ NH_4Cl \rightarrow NH_4^+ + Cl^- \] 2. **Analyzing the Hydrolysis of Ions:** - The chloride ion (Cl^-) is the conjugate base of a strong acid (HCl) and does not undergo hydrolysis. Therefore, it does not affect the pH of the solution. - The ammonium ion (NH4^+) is a weak acid and can undergo hydrolysis: \[ NH_4^+ + H_2O \rightleftharpoons NH_3 + H_3O^+ \] This reaction shows that the ammonium ion donates a proton (H^+) to water, forming hydronium ions (H3O^+). 3. **Effect of Hydrolysis on pH:** The production of H3O^+ ions from the hydrolysis of NH4^+ results in an increase in the concentration of hydronium ions in the solution. Since H3O^+ ions contribute to acidity, the pH of the solution will be less than 7. 4. **Conclusion:** Therefore, the reason the pH of the resulting solution is not equal to 7 is due to the hydrolysis of the ammonium ion, which produces H3O^+ ions, making the solution acidic. ### Final Answer: The pH of the resulting solution of ammonium chloride in pure water is not 7 because the ammonium ion (NH4^+) undergoes hydrolysis to produce hydronium ions (H3O^+), resulting in an acidic solution.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • IONIC EEQUILIBRIUM

    NARENDRA AWASTHI ENGLISH|Exercise One or More Answer is/are Correct|1 Videos
  • IONIC EEQUILIBRIUM

    NARENDRA AWASTHI ENGLISH|Exercise Assertin-Reason Type Questions|1 Videos
  • IONIC EEQUILIBRIUM

    NARENDRA AWASTHI ENGLISH|Exercise Level- 2|35 Videos
  • GASEOUS STATE

    NARENDRA AWASTHI ENGLISH|Exercise Subjective problems|15 Videos
  • SOLID STATE

    NARENDRA AWASTHI ENGLISH|Exercise Subjective Problems|13 Videos

Similar Questions

Explore conceptually related problems

Hydrolysis is an acid-basedreaction of a cation or anion or both ions of a salt with water, Resultan solution of hydrolysis may be acidic, basic or netural. The anion A^(-) which is a weakeer base than OH^(-) and which his its conjugate acid HA stronger then water but weaker than H_(3)O shown the phenomenon of hydrolysis Ex : CH_(3)COO^(-),CN^(-),NO_(2)^(-) etc. The contion B^(+) which is a weaker acid than H_(3)^(+) which is a weaker acid then H_(3)^(+) and which has its conjugate base BOH stronger than water but weak than OH^(-) shown the phenmenon of hydrolysis Ex : NH_(4)^(+)C_(6)H_(5)NH^(+),N_(2)H_(5)^(+) etc. The hydrolysis constant of anion and cation are given by A^(-)(aq.)+H_(2)O(l)hArrHA(aq.)+OH^(-)(aq) " " K_(h)=(K_(w))/(K_(a))rArr([HA(aq.)][OH^(-)(aq.)])/([A^(-)(aq.)]) B^(+)(aq.)+H_(2)O(l)hArrBOH(aq.)+H^(+)(aq.) " " K_(h)=(K_(w))/(K_(b))rArr([BOH(aq.)][H^(+)(aq.)])/([B^(-)(aq.)]) Which of the following statement is true

Hydrolysis is an acid-basedreaction of a cation or anion or both ions of a salt with water, Resultan solution of hydrolysis may be acidic, basic or netural. The anion A^(-) which is a weakeer base than OH^(-) and which his its conjugate acid HA stronger then water but weaker than H_(3)O shown the phenomenon of hydrolysis Ex : CH_(3)COO^(-),CN^(-),NO_(2)^(-) etc. The contion B^(+) which is a weaker acid than H_(3)^(+) which is a weaker acid then H_(3)^(+) and which has its conjugate base BOH stronger than water but weak than OH^(-) shown the phenmenon of hydrolysis Ex : NH_(4)^(+)C_(6)H_(5)NH^(+),N_(2)H_(5)^(+) etc. The hydrolysis constant of anion and cation are given by A^(-)(aq.)+H_(2)O(l)hArrHA(aq.)+OH^(-)(aq) " " K_(h)=(K_(w))/(K_(a))rArr([HA(aq.)][OH^(-)(aq.)])/([A^(-)(aq.)]) B^(+)(aq.)+H_(2)O(l)hArrBOH(aq.)+H^(+)(aq.) " " K_(h)=(K_(w))/(K_(b))rArr([BOH(aq.)][H^(+)(aq.)])/([B^(-)(aq.)]) select the correct statement :

Knowledge Check

  • Which of the following salts will give basic solution on hydrolysis ?

    A
    `NH_(4)Cl`
    B
    `KCl`
    C
    `K_(2)CO_(3)`
    D
    `(NH_(4))_(2)CO_(3)`
  • The salt which on hydrolysis forms acid is ______

    A
    Iron chloride
    B
    Aluminium acetate
    C
    Sodium chloride
    D
    All the above
  • Similar Questions

    Explore conceptually related problems

    Hydrolysis is an acid-basedreaction of a cation or anion or both ions of a salt with water, Resultan solution of hydrolysis may be acidic, basic or netural. The anion A^(-) which is a weakeer base than OH^(-) and which his its conjugate acid HA stronger then water but weaker than H_(3)O shown the phenomenon of hydrolysis Ex : CH_(3)COO^(-),CN^(-),NO_(2)^(-) etc. The contion B^(+) which is a weaker acid than H_(3)^(+) which is a weaker acid then H_(3)^(+) and which has its conjugate base BOH stronger than water but weak than OH^(-) shown the phenmenon of hydrolysis Ex : NH_(4)^(+)C_(6)H_(5)NH^(+),N_(2)H_(5)^(+) etc. The hydrolysis constant of anion and cation are given by A^(-)(aq.)+H_(2)O(l)hArrHA(aq.)+OH^(-)(aq) " " K_(h)=(K_(w))/(K_(a))rArr([HA(aq.)][OH^(-)(aq.)])/([A^(-)(aq.)]) B^(+)(aq.)+H_(2)O(l)hArrBOH(aq.)+H^(+)(aq.) " " K_(h)=(K_(w))/(K_(b))rArr([BOH(aq.)][H^(+)(aq.)])/([B^(-)(aq.)]) Calculate percentage degreeof hydrolysis in a 0.1 M solution of CH_(3)COONa.(K_(a)"of"CH_(3)COOH=10^(-5))

    Salt hydrolysis is an acid - base reaction of cation or anion or both ions of salt with water . The resultant solution after hydrolysis may be acidic , basic or neutral . The anion X^(-) which is weaker base than OH^(-) and which has its conjugate acid HX stronger than water but weaker than H_(3)O^(+) shows the phenomenon of hydrolysis , e.g CH_(3)COO^(-) , NO_(2)^(-) , CN^(-) etc. The cation M^(+) which is weaker acid than H_(3)O^(+) and which has its conjugate base MOH stronger than water but weaker than OH^(-) shows the phenomenon of hydrolysis , e.g N_(2)H_(5)^(+), C_(6)H_(5)NH^(+),NH_(4)^(+) etc . The degree of hydrolysis of a salt of weak acid (HA) and weak base (BOH) in its 0.1 M solution is found to be 0.1 .If the molarity of the solution is 0.05 M , the percentage hydrolysis of salt should be :

    Degree hydrolysis (h) of a salt of weak acid and a strong base is given by

    The product of acid hydrolysis of is

    What is obtained by hydrolysis of nucleic acid?

    Hydrolysis constant for a salt of weak acid and weak base would be