Ionic Equilibrium: Acids & Bases — Practice Questions

Free NEET Chemistry multiple-choice questions on Ionic Equilibrium: Acids & Bases. Attempt each question and reveal the answer with a full explanation.

Which of the following is an acidic salt? NaHSO 4 Na 2SO 4 CH 3COONa NaCl Which of the following is the conjugate acid of NH 2 - ? NH 3 NH 4 + NH 2- N 2H 4 Which of the following is not a Bronsted-Lowry conjugate acid-base pair? H 3O + / OH - NH 4 + / NH 3 H 2SO 4 / HSO 4 - CH 3COOH / CH 3COO - Which species acts as a Lewis base in the formation of an adduct with BF 3 ? NH 3 AlCl 3 H + BeCl 2 For a salt of strong acid and weak base, the hydrolysis constant K h is related to K b and K w as: K h = K w / K b K h = K w / K a K h = K w K b K h = K a / K w Which of the following hydroxides is amphoteric? Be(OH) 2 Mg(OH) 2 Ca(OH) 2 Sr(OH) 2 Which of the following hydracids has the highest acid strength? HI HF HCl HBr Which of the following acidic strengths is correct for the following oxyacids of chlorine? HClO 4 > HClO 3 > HClO 2 > HClO HClO > HClO 2 > HClO 3 > HClO 4 HClO 3 > HClO 4 > HClO 2 > HClO HClO 4 > HClO 2 > HClO 3 > HClO According to Bronsted-Lowry concept, the conjugate base of H 2O and conjugate acid of NH 3 are respectively: OH - and NH 4 + H 3O + and NH 2 - OH - and NH 2 - H 3O + and NH 4 + Which of the following salts will give an alkaline solution on hydrolysis? Na 2CO 3 NH 4Cl NaCl KNO 3 Which salt is most likely to have a pH less than 7 in an aqueous solution? NH 4Cl NaCl CH 3COONa K 2SO 4 According to the Bronsted-Lowry theory, which of the following acts as the conjugate acid of HSO 4 - ? H 2SO 4 SO 4 2- H 3SO 4 + H 2SO 3 Which of the following is an example of a Lewis acid? BCl 3 NH 3 H 2O F - In the titration of CH 3COOH with NaOH , the pH at the equivalence point is: Greater than 7 Less than 7 Exactly 7 Depends on concentration Which of the following is the strongest acid among the given options? HClO 4 H 2 SO 4 HNO 3 H 3 PO 4 What is the conjugate acid of the carbonate ion ( CO 3 2- )? HCO 3 - H 2 CO 3 OH - CO 2 Which of the following molecules acts as a Lewis base due to the presence of a lone pair on the central atom? PCl 3 BF 3 AlCl 3 CH 4 Which of the following is the conjugate base of HSO 4 - ? SO 4 2- H 2SO 4 OH - H 3O + Following solutions were prepared by mixing different volumes of NaOH and HCl of different concentrations. Which of them will be exactly neutral? 100 mL of M/10 HCl + 100 mL of M/10 NaOH 55 mL of M/10 HCl + 45 mL of M/10 NaOH 10 mL of M/10 HCl + 90 mL of M/10 NaOH 75 mL of M/5 HCl + 25 mL of M/5 NaOH Which of the following salts will result in a solution with pH > 7 upon hydrolysis? NaCN NH 4Cl KCl AlCl 3 Which of the following species cannot act as a Bronsted acid? O 2- NH 4 + H 2O HCO 3 - Which of the following is the correct order of acid strength for the halogen hydracids? HI > HBr > HCl > HF HF > HCl > HBr > HI HCl > HF > HI > HBr HI > HCl > HBr > HF Which of the following is a Lewis base? PH 3 BF 3 AlCl 3 FeCl 3 Identify the Lewis acid in the reaction: AlCl 3 + Cl - [AlCl 4] - . AlCl 3 Cl - [AlCl 4] - None of these Which of the following is an example of an amphoteric hydroxide? Be(OH) 2 Mg(OH) 2 Ca(OH) 2 Ba(OH) 2 The conjugate acid of HPO 4 2- is: H 2PO 4 - H 3PO 4 PO 4 3- H 2PO 4 2- Identify the species that can act as both Bronsted acid and Bronsted base. HCO 3 - CO 3 2- H 3O + NH 4 + A weak acid, HA, has a K a of 1.00 10 -5 . If 0.100 mole of this acid dissolved in one litre of water, the percentage of acid dissociated at equilibrium is closest to 1.00% 99.9% 0.100% 99.0% Which one of the following ionic species has the greatest proton affinity to form stable compound? NH 2 - F - I - HS - Which one of the following orders correctly represents the increasing acid strengths of the given acids? HOClO < HOCl < HOClO 3 < HOClO 2 HOClO 2 < HOClO 3 < HOClO < HOCl HOClO 3 < HOClO 2 < HOClO < HOCl HOCl < HOClO < HOClO 2 < HOClO 3 The ionization constant of ammonium hydroxide is 1.77 10 -5 at 298 K . Hydrolysis constant of ammonium chloride - 5.65 10 -12 5.65 10 -10 6.50 10 -12 5.65 10 -13 What is the [ OH -] in the final solution prepared by mixing 20.0 mL of 0.050 M HCl with 30.0 mL of 0.10 M Ba(OH)2 ? - 0.12 M 0.10 M 0.40 M 0.0050 M Which of the following salts will give highest pH in water ? KCl NaCl Na2CO3 CuSO4 The conjugate base of HCO 3 - is: CO 3 2- H 2CO 3 CO 2 OH - Conjugate base for Brönsted acids H2O and HF are : H3O+ and H2F+ , respectively OH - and H2F+ , respectively H3O+ and F - , respectively OH - and F - , respectively Which of the following aqueous solutions will have the highest pH? 0.1 M Na 2CO 3 0.1 M NaCl 0.1 M ZnCl 2 0.1 M NH 4Cl Which species acts as the strongest Bronsted-Lowry base? OH - ClO 4 - HSO 4 - Cl - The dissociation constant of HCN is 4.8 10 -10 . What is the hydrolysis constant ( K h ) of KCN at 25 ∘C ? 2.08 10 -5 4.8 10 -24 2.08 10 -4 4.8 10 -10 The ionisation constant of HF is 3.2 10 -4 . The degree of dissociation of 0.02 M solution is: 0.126 0.016 0.08 0.64 Identify the correct plot for the titration of a strong acid ( HCl ) with a strong base ( NaOH ). pH starts near 1, remains flat, rises sharply at equivalence point to 7, plateaus near 13 pH starts near 13, drops sharply at equivalence point to 7, plateaus near 1 pH starts at 7 and increases linearly pH remains constant throughout the titration The hydrolysis constant ( K h ) for a salt of a weak acid ( HA ) and a weak base ( BOH ) is: K w / (K a K b ) K w / K a K w / K b K a K b / K w The degree of dissociation ( ) of a 0.1 M HCN solution ( K a = 4.9 10 -10 ) is approximately: 7 10 -5 7 10 -6 4.9 10 -9 0.01 The K a of acetic acid is 1.8 10 -5 at 25 C . The K b of its conjugate base (acetate ion) is: 5.56 10 -10 1.8 10 -5 1.0 10 -14 5.56 10 -9 Which indicator is most suitable for the titration of a weak base like NH 4 OH against a strong acid like HCl ? Methyl orange Phenolphthalein Thymol blue Any of these Which of the following is an amphiprotic species? HPO 4 2- PO 4 3- H 3PO 4 HCl What is the hydroxide ion concentration in a solution prepared by dissolving 0.37 g of Ca(OH) 2 in water to make 500 mL of solution? (Molar mass of Ca(OH) 2 = 74 g/mol ) 0.02 M 0.01 M 0.05 M 0.10 M The leveling effect of water refers to the fact that: All strong acids appear equally strong in water. Water can act as both an acid and a base. Water ionizes to a small extent. pH of water is always 7. Which of the following is the correct order of acidic strength for the oxoacids of phosphorus? H 3PO 2 > H 3PO 3 > H 3PO 4 H 3PO 4 > H 3PO 3 > H 3PO 2 H 3PO 3 > H 3PO 2 > H 3PO 4 H 3PO 2 > H 3PO 4 > H 3PO 3 Which of the following orders of Lewis basicity is correct for the Group 15 hydrides? NH 3 > PH 3 > AsH 3 > SbH 3 SbH 3 > AsH 3 > PH 3 > NH 3 NH 3 > AsH 3 > PH 3 > SbH 3 PH 3 > NH 3 > AsH 3 > SbH 3 What is the concentration of OH - ions in a solution obtained by mixing equal volumes of 0.1 M HCl and 0.2 M NaOH ? 0.05 M 0.1 M 0.01 M 0.2 M Which of the following salts undergoes cationic hydrolysis in water? NH 4Cl CH 3COONa KNO 3 Na 2CO 3 A solution of NaHCO 3 in water is: Alkaline Acidic Neutral Highly acidic Which of the following aqueous solutions will be most acidic? 0.1 M FeCl 3 0.1 M NaCl 0.1 M CH 3COONa 0.1 M Na 2CO 3 At 25 C , the dissociation constant of a base, BOH, is 1.0 10 -12 . The concentration of hydroxyl ions in 0.01M aqueous solution of the base would be :- 1.0 10 -6 mole L -1 1.0 10 -7 mole L -1 2.0 10 -6 mole L -1 1.0 10 -5 mole L -1 What is the correct relationship between the pHs of isomolar solutions of sodium oxide (pH 1 ), sodium sulphide (pH 2 ), sodium selenide (pH 3 ) and sodium telluride (pH 4 ) ? pH 1 < pH 2 < pH 3 < pH 4 pH 1 > pH 2 > pH 3 > pH 4 pH 1 < pH 2 < pH 3 pH 4 pH 1 > pH 2 pH 3 > pH 4 Which among the following is the strongest acid in aqueous solution? HI HCl HBr HF The dissociation constants for acetic acid and HCN at 25 C are 1.5 10 -5 and 4.5 10 -10 , respectively. The equilibrium constant for the equilibrium – CN - + CH 3COOH HCN + CH 3COO - would be : 3.0 10 4 3.0 10 5 3.0 10 -5 3.0 10 -4 Phosphoric acid ionizes in three steps with their ionization constant values K a 1 , K a 2 and K a 3 , respectively, while K is the overall ionization constant. Which of the following statements are true? A. K = K a 1 + K a 2 + K a 3 B. H3PO4 is a stronger acid than H2PO4 - and HPO4 2- C. K a 1 > K a 2 > K a 3 D. K a 1 = K a 3 + K a 2 2 Choose the correct answer from the options given below : A, B and C only A and B only A and C only B, C and D only The pH of a solution containing 0.1 M CH 3COOH and 0.1 M HCl will be approximately: 1.0 2.8 7.0 4.7 Which of the following is a Lewis acid? BF 3 NH 3 H 2O F - According to the Lewis concept, which of the following is not a base? BF 3 NH 3 H 2O OH - Which of the following salts will NOT undergo hydrolysis in water? KNO 3 NaCN NH 4Cl CH 3COONa