Question

Chapter 15 1) The name of HClO is ________. a. hydrogen chloride b. hydrochloric acid c. chloric acid d. perchloric acid e. hypochlorous acid 2) Identify the Bronsted-Lowry acid in the following reaction. H2O + CO3 2- (aq) ? HCO3 - (aq) + OH- (aq) a. H2O b. CO3 2- c. HCO3 - d. OHe. H2CO3 3) What is the [H3O+] in a solution with [OH- ] = 1.0 � 10-12 M? a. 1.0 � 10-12 M b. 1.0 � 102 M c. 1.0 � 10-7 M d. 1.0 � 10-8 M e. 1.0 � 10-2 M 4) What is the [OH- ] in a solution that has a [H3O+] = 1.0 � 10-6 M? a. 1.0 � 10-2 M b. 1.0 � 10-6 M c. 1.0 � 10-8 M d. 1.0 � 10-10 M e. 1.0 � 10-12 M 5) The [H3O+] of a solution with pH = 2.0 has a concentration of ________. a. 10 M b. 0.1 M c. 1 � 102 M d. 1 � 10-2 M e. 1 � 10-12 M 6) Which of the following is the strongest acid? a. H3PO4 b. NH4 + c. NaOH d. H2CO3 e. HCl 7) Which of the following is correctly identified? a. NH3, strong acid b. NaOH, strong base c. HCl, weak acid d. H2CO3, strong acid e. Ca(OH)2, weak base 8) Ammonia is a weak base because a. it is a dilute solution. b. it is only slightly soluble in water. c. it cannot hold on to its hydroxide ions. d. it produces few hydroxide ions in water. e. it is completely ionized in aqueous solution. 9) Which of the following is a neutralization reaction? a. KCl + NaNO3 ? KNO3 + NaCl b. HNO3 + KOH ? H2O + KNO3 c. H2O + SO3 ? H2SO4 d. 4Na + O2 ? 2 Na2O e. 2 NO2 ? 2NO + O2 10) Which of the following is a buffer system? a. NaCl and NaNO3 b. HCl and NaOH c. H2CO3 and KHCO3 d. NaCl and NaOH e. H2O and HCl

Answer 1

1) The name of HClO is hypochlorous acid - Cl with +1 oxidation state

Reason: For ' Cl ' four possible positive oxidation states

Oxidation state	prefix - suffix (while naming acid)
+1	hypo - ous( acid)
+3	no prefix - ous (  acid)
+5	no prefix -ic (  acid)
+7	per -ic (  acid)

2) Bronsted Acid is Proton Donor

• In the given reaction H₂O acts as a proton donor. Therefore  H₂O is Bronsted acid

3) The water ionisation constant Kw = [H₃O⁺] [OH^-] = (1 X 10^-7) x (1x 10^-7) = 1x 10^-14 M

Therfore if  [OH^-] = (1x 10^-12)

then   [H₃O⁺]= 1x 10^-2 M

4. What is the [OH^- ] in a solution that has a [H₃O⁺] = 1.0 x 10^-6 M

Similar to previous one.

[OH^- ] = 1.0 x 10^-8 M

5) The [H₃O⁺] of a solution with pH = 2.0 has a concentration of ________.

pH = -log [H₃O⁺]

therefore, [H₃O⁺] = 10^-pH

   ⁼ 10^-2 M

6) Which of the following is the strongest acid?

Ans. a. H₃PO₄

because it is ready to donate proton due to resonance stabilisation.

7) Which of the following is correctly identified?

Ans: b. NaOH, strong base

Because

a. NH₃, weak base c. HCl, strong acid d. H₂CO₃, weak acid

8) Ammonia is a weak base because

it produces few hydroxide ions in water.

9) Which of the following is a neutralization reaction?

Ans : HNO₃ + KOH ? H₂O + KNO₃

only This reaction involves acid and base

10) Which of the following is a buffer system?

Ans:  H₂CO₃ and KHCO₃

Buffer solution : mixture of weak acid and its corresponding salt.