Self Studies

Equilibrium Test 14

Result Self Studies

Equilibrium Test 14
  • Score

    -

    out of -
  • Rank

    -

    out of -
TIME Taken - -
Self Studies

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Self Studies Self Studies
Weekly Quiz Competition
  • Question 1
    1 / -0

    The following equilibrium exists in aqueous solution

    CH3COOH  CH3COO- + H+

    If dilute HCl is added:

    Solution

    If dilute HCl is added then concentration of H+ ions will increase so according to Lechatelier's principle equilibrium will shift in backward direction. So acetate ion concentration will decrease.

  • Question 2
    1 / -0

    Consider KA, the potassium salt of a weak acid, HA. If a sample of KA is dissolved in water, with no other substances added, which of the following statements is true (approximately)?

    Solution

    The correct answer is option C
    [HA] = [OH–]
    The reaction is: A– + H2O ⇌ HA + OH–

  • Question 3
    1 / -0

    Which of the following is an example of basic buffer?

    Solution

    The correct answer is Option B.

    NH4Cl is a strong electrolyte hence, dissociates completely, NH4OH is a weak electrolyte. Its dissociation is further suppressed by common ion NH4+ provided by NH4Cl in the solution.
    NH4Claq  ⇌ NH4aq+ +Claq−
    NH4OHaq ⇌ NH4aq++ OHaq−
    This solution acts as a basic buffer and maintains its pH around 9.25. It is capable of resisting the change in pH in addition to a small amount of acid or alkali.
    To Explain:
    If a small amount of HCl is added to this solution, H+
    ions of HCl get neutralized by OH− ions already present and more of NH4
    ​OH molecules get ionized to compensate for the loss of OH− ions. Thus pH practically, remains constant.
    If a small amount of NaOH is added to this solution, OH− ions of NaOH combine with NH4+ ions already present in large numbers forming weakly ionized NH4OH. Thus, pH of solution remains practically unchanged.

  • Question 4
    1 / -0

     If the value of the solubility product for AgBr is 4.0 x 10-12 at 25°C, calculate the solubility of AgBr(s) in water.

    Solution

    Ksp = 4.0 x 10-12 
    For AB type salt, Solubility = Ksp1/2
    = (4.0 x 10-12)1/2
    = 2 x 10-6

  • Question 5
    1 / -0

    A mixture of CH3COOH and CH3COONa behaves as

    Solution

    Mixtures of CH3COOH and CH3COONa are called acidic buffer. Since the constitution of this buffer is a weak acid and its constituting salt, it is called Acidic buffer.

  • Question 6
    1 / -0

    Role of NH4Cl in qualitative analysis of third group cations

    Solution

    The correct answer is option D
    Common ion effect is observed when a solution of weak electrolyte is mixed with a solution of strong electrolyte, which provides an ion common to that provided by weak electrolyte.
    The NH4OH is a weak base and it does not ionise completely. Thus, due to presence of common ion NH4+ in NH4Cl, it suppresses the ionisation of weak base NH4OH in order to decrease the OH- concentration so that higher group cations will not get precipitated.
    Thus the pair NH4​OH+NH4​Cl shows a common ion effect. 
    Ammonium chloride suppresses the ionization of ammonium hydroxide
    .

  • Question 7
    1 / -0

    When the value of Kc is very small then

    Solution

    Kc = Product of Molar conc. of products/ Product of molar conc. of reactants 

    If Kc is less this clearly means that the product of the molar conc. Of reactants is more or the reaction is less in forward direction and more in the backward direction.

  • Question 8
    1 / -0

    A mixture of NH4Cl and NH4OH shows no change in pH upon addition small amount of HCl. This is because it is

    Solution

    A mixture of weak base and its salt with a strong acid serves as an basic buffer which resists changes in pH upon addition of small amount of acid or base.

     

     

  • Question 9
    1 / -0

     We eat a variety of foods still pH of our blood does not change every time. The reason is

    Solution

    The correct answer is option C
    pH of blood remains constant because of the buffer system present in the blood. Acid-base buffers confer resistance to a change in the pH of a solution when hydrogen ions (protons) or hydroxide ions are added or removed. An acid-base buffer typically consists of a weak acid, and its conjugate base (salt).It used to neutralized the extra added protons or OH- in blood.The buffer for maintaining acid-base balance in the blood is the carbonic-acid-bicarbonate buffer.So pH of blood remains even after eating spicy food.

  • Question 10
    1 / -0

     For HF, pKa = 3.45. What is the pH of an aqueous buffer solution that is 0.1M HF (aq) and 0.300 M KF (aq)?

    Solution

    Given, pKa = 3.45
    Concentration of HF = 0.1 M, concentration of KF = 0.300 M
    For acidic buffer;
    pH = pKa + log [salt of weak acid]/[weak acid]
    = 3.45 + log0.3/0.1
    = 3.45 + 0.48
    = 3.93

Self Studies
User
Question Analysis
  • Correct -

  • Wrong -

  • Skipped -

My Perfomance
  • Score

    -

    out of -
  • Rank

    -

    out of -
Re-Attempt Weekly Quiz Competition
Self Studies Get latest Exam Updates
& Study Material Alerts!
No, Thanks
Self Studies
Click on Allow to receive notifications
Allow Notification
Self Studies
Self Studies Self Studies
To enable notifications follow this 2 steps:
  • First Click on Secure Icon Self Studies
  • Second click on the toggle icon
Allow Notification
Get latest Exam Updates & FREE Study Material Alerts!
Self Studies ×
Open Now