Question 1

A catalyst is a substance that increases the rate of reaction by lowering the activation energy. Which of the following statements about catalysts is correct?

Accepted Answer

Catalysts lower activation energy by offering an alternative reaction mechanism but remain unchanged and do not affect ΔH or equilibrium position.

Question 2

The complex [Ni(CO)₄] is diamagnetic. This indicates that nickel in this complex has:

Accepted Answer

Diamagnetic complexes have no unpaired electrons; CO is a strong field ligand causing electron pairing in the d-orbitals of Ni(0).

Question 3

The rate of a chemical reaction is defined as the change in concentration of a reactant or product per unit time. If the concentration of a reactant decreases from 0.8 M to 0.2 M in 3 seconds, what is the average rate of reaction?

Accepted Answer

Average rate = Δ[concentration]/Δtime = (0.8 - 0.2) M / 3 s = 0.6 M / 3 s = 0.2 M/s.

Question 4

The activation energy (Eₐ) of a reaction is the minimum energy required for reactants to form products. How does increasing the temperature of a reaction affect the number of collisions with energy ≥ Eₐ?

Accepted Answer

Higher temperature increases the kinetic energy of molecules, causing more collisions to exceed the activation energy threshold.

Question 5

What is the coordination number of the central metal ion in the complex [Co(NH₃)₆]³⁺?

Accepted Answer

The coordination number equals the total number of ligand donor atoms bonded to the central metal ion; six NH₃ molecules each donate one electron pair, giving coordination number 6.

Question 6

In the complex [CuCl₄]²⁻, what is the oxidation state of copper?

Accepted Answer

Using the oxidation state rule: copper oxidation state + 4(−1 from Cl⁻) = −2 overall charge, solving gives Cu as +2.

Question 7

If 96,500 C of charge is passed through a CuSO₄ solution using copper electrodes, what mass of copper is deposited at the cathode? (Molar mass of Cu = 64 g/mol)

Accepted Answer

Using Faraday's law: mass = (charge × molar mass)/(n × Faraday constant) = (96,500 × 64)/(2 × 96,500) = 64 g.

Question 8

A solution contains 36 g of glucose (C₆H₁₂O₆) dissolved in 1000 g of water. Calculate the molality of the solution. (Molar mass of glucose = 180 g/mol)

Accepted Answer

Molality = (moles of solute) / (mass of solvent in kg) = (36/180) / 1 = 0.2 m.

Question 9

What is the mole fraction of solute in a solution containing 46 g of ethanol (C₂H₅OH) dissolved in 72 g of water? (Molar mass: ethanol = 46 g/mol, water = 18 g/mol)

Accepted Answer

Moles of ethanol = 46/46 = 1; moles of water = 72/18 = 4; mole fraction = 1/(1+4) = 0.2, or approximately 0.25.

Question 10

For a first-order reaction, the integrated rate law is given by ln[A] = ln[A]₀ - kt. If the half-life of a first-order reaction is 10 minutes, what will be the half-life if the initial concentration is doubled?

Accepted Answer

For first-order reactions, half-life is independent of initial concentration and depends only on the rate constant k.

Question 11

Which of the following is a colligative property of solutions?

Accepted Answer

Boiling point elevation depends only on the number of solute particles, not their identity, making it a colligative property.

Question 12

For a zero-order reaction, the integrated rate law is [A] = [A]₀ - kt. If a zero-order reaction has a rate constant of 0.05 M/s and initial concentration of 2 M, how long will it take for the concentration to become zero?

Accepted Answer

Using [A] = [A]₀ - kt, when [A] = 0: 0 = 2 - (0.05)t, so t = 2/0.05 = 40 seconds.

Question 13

A solution is prepared by dissolving 68 g of sucrose (C₁₂H₂₂O₁₁) in sufficient water to make 500 mL of solution. Calculate the molarity. (Molar mass of sucrose = 342 g/mol)

Accepted Answer

Molarity = (moles of solute) / (volume in L) = (68/342) / 0.5 = 0.4 M.

Question 14

Which of the following ligands is classified as a bidentate ligand?

Accepted Answer

Ethylenediamine has two nitrogen donor atoms that can simultaneously coordinate to a central metal ion, making it a bidentate ligand.

Question 15

A 2.0 M solution of NaCl is prepared. What is the mass of NaCl required to prepare 500 mL of this solution? (Molar mass of NaCl = 58.5 g/mol)

Accepted Answer

Mass = Molarity × Volume (L) × Molar mass = 2.0 × 0.5 × 58.5 = 58.5 g.

Question 16

In an electrochemical cell, which electrode is the site of oxidation?

Accepted Answer

The anode is where oxidation occurs (loss of electrons), while the cathode is where reduction occurs.

Question 17

What is the standard cell potential (E°cell) if E°cathode = +0.80 V and E°anode = −0.44 V?

Accepted Answer

E°cell = E°cathode − E°anode = 0.80 − (−0.44) = 1.24 V.

Question 18

Which of the following statements is true for a galvanic cell?

Accepted Answer

In a galvanic cell, electrons generated at the anode travel through the external circuit to the cathode.

Question 19

In the electrolysis of molten NaCl, the product formed at the cathode is:

Accepted Answer

At the cathode (reduction site), Na⁺ ions gain electrons to form sodium metal: Na⁺ + e⁻ → Na.

Question 20

What is the IUPAC name of the complex [Pt(NH₃)₄]²⁺?

Accepted Answer

IUPAC nomenclature: prefix 'tetra' for four NH₃ ligands + 'ammine' + metal name 'platinum' + oxidation state (II) in parentheses + 'ion'.

Agniveer Army Technical Applied Chemistry Questions

Applied Chemistry Practice Questions — Graded Difficulty

Study by Subtopic — Applied Chemistry

Study Next — Chemistry Topics