MCQ Collection
Pakistan MCQs
Practice Pakistan questions with answers and explanations.
Choose an option to check your answer.
Correct Answer: C. Reaction of an acid and base to form water and a salt
Explanation:
In many aqueous neutralizations, H+ and OH- form water.
The remaining ions form a salt.
Choose an option to check your answer.
Correct Answer: C. 4
Explanation:
For the 1:1 equation, Kc=[B]/[A].
Kc=0.80/0.20=4.
Choose an option to check your answer.
Correct Answer: D. A substance changing color over a characteristic pH range
Explanation:
Acid-base indicators have differently colored protonated and deprotonated forms.
They help identify titration endpoints.
Choose an option to check your answer.
Correct Answer: D. 1
Explanation:
The equilibrium expression is Kc=[B]/[A]^2.
Kc=0.25/(0.50)^2=1.
Choose an option to check your answer.
Correct Answer: A. A ratio with the equilibrium-expression form using current concentrations or pressures
Explanation:
Q can be calculated at any stage.
Comparing Q with K predicts the direction of net change.
Choose an option to check your answer.
Correct Answer: A. Toward products
Explanation:
Because Q<K, more products must form.
The reaction proceeds forward until Q reaches K.
Choose an option to check your answer.
Correct Answer: B. Toward products
Explanation:
The mixture contains too little product relative to equilibrium.
Net forward reaction increases Q toward K.
Choose an option to check your answer.
Correct Answer: B. A substance that increases H+ concentration in water
Explanation:
Arrhenius acids produce hydrogen ions in aqueous solution.
The model applies specifically to water.
Choose an option to check your answer.
Correct Answer: C. Toward reactants
Explanation:
The mixture contains too much product relative to equilibrium.
Net reverse reaction lowers Q toward K.
Choose an option to check your answer.
Correct Answer: C. A substance that increases OH- concentration in water
Explanation:
Arrhenius bases increase hydroxide-ion concentration in water.
Many metal hydroxides fit this definition.
Choose an option to check your answer.
Correct Answer: D. How an equilibrium system responds to a disturbance
Explanation:
An equilibrium shifts to oppose an imposed change.
Changes in concentration, pressure, or temperature may shift position.
Choose an option to check your answer.
Correct Answer: D. A proton donor
Explanation:
Brønsted-Lowry acid-base reactions involve proton transfer.
The acid loses H+ to a base.
