Free Acids, Bases and Salts MCQs with Answers

311. Which compound is formed when Ammonium hydroxide is added to silver chloride?

• A. [Ag(NH3)2]Cl
• B. [Ag(NH3)]Cl
• C. [Ag(NH3)4]Cl
• D. [Ag(NH3)6]Cl

Explanation: When ammonium hydroxide is added to silver chloride, the silver chloride dissolves in the ammonia to form a diamine complex: [Ag(NH3)2]Cl. This occurs because ammonia acts as a ligand, donating a pair of electrons to silver ions, forming a stable complex. The correct option, [Ag(NH3)2]Cl, reflects this complex formation. Other options like [Ag(NH3)]Cl, [Ag(NH3)4]Cl, and [Ag(NH3)6]Cl are incorrect as they suggest incorrect stoichiometries and coordination numbers that do not occur in this reaction.

312. Which one of the following salts will produce an alkaline solution when dissolved in water?

• A. NH4Cl
• B. NaNO3
• C. Na2CO3
• D. Na2SO4

Explanation: The correct answer is Na2CO3. Sodium carbonate forms an alkaline solution because it undergoes hydrolysis in water, releasing hydroxide ions (OH-) which increase the pH. In contrast:NH4Cl forms an acidic solution due to ammonium ions generating hydronium ions.NaNO3 remains neutral as neither ion affects pH significantly.Na2SO4 also results in a neutral solution for similar reasons to NaNO3.

313. The compound used in borax bead test for the detection of basic redicals to form colored bead is:

• A. H2BO2
• B. (C2H5)3BO3
• C. Ca2B6O115H2O
• D. Na2B4O710H2O

Explanation: Per one molecule of borax, there are 10 molecules of water of crystallization. Hence, metaborate is formed in the borax bead test.

314. The number of ejected photoelectrons increases with increase. is strong electrolyte?

• A. Ca(OH)2
• B. SiCl4
• C. KCl
• D. SrCl2

Explanation: KCl is a strong electrolyte because it fully dissociates into ions (K+ and Cl-) in water, allowing efficient conduction of electricity. Ca(OH)2 is a weak base and weak electrolyte, which means it does not fully dissociate into ions. SiCl4 does not dissociate at all in water, making it a non-electrolyte. SrCl2 was incorrectly described; it is a strong electrolyte as it also fully dissociates in solution.