A practice set of chemistry questions covering physical, organic and inorganic topics. It works as a short self-check on concepts, reactions and problem solving, with answers available once you finish. Return to it whenever you want to confirm that earlier revision has stuck.
In the gas phase, basicity increases with alkyl substitution due to the inductive effect: NH₃ < CH₃NH₂ < (CH₃)2NH < (CH₃)3N, unaffected by solvation. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Chemical Bonding, Topic: Hybridization of nitrogen in CH₃NH₂, sp³ hybridization, pyramidal geometry.
[Fe(H₂O)6]^{3+ (Fe³⁺, d⁵ ) with weak field H₂O is high spin ( t_{2g³ e_g² ), with 5 unpaired electrons, the highest among the options. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
[Fe(CO)5] has 5 CO ligands around Fe(0), adopting a trigonal bipyramidal geometry, unlike the tetrahedral, square planar, or octahedral options. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: The oxidation state of sulfur in SO_3 is: These values define the system as per NCERT data. Formula: In SO_3, O is -2, so 3(-2) + S = 0, S = +6, as sulfur shares electrons with three oxygen atoms.. This is standard NCERT relation. Substitution & Calculation: Substituting values and simplifying step by step as per NCERT method. Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: The initial rate of a reaction is 1.2 × 10⁻³mol L^{-1 s^{-1 when [A] = 0.2 M and [B] = 0.3 M. If the order is 1 with respect to A and 1 with respect to B, what is k in L mol^{-1 s^{-1 ? These values define the system as per NCERT data. Formula: k = fracRate[A][B] = frac1.2 × 10⁻³⁰.2 × 0.3 = 0.02 .. This is standard NCERT relation. Substitution & Calculation: Substituting values and simplifying step by step as per NCERT method. Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: A solution of two volatile liquids A and B has a total vapor pressure of 290 mm Hg. If the vapor pressure of pure A is 450 mm Hg and that of pure B is 150 mm Hg, what is the mole fraction of A in the solution? These values define the system as per NCERT data. Formula: Using Raoult's law: p_{total = x_A p_A⁰ + (1 - x_A) p_B⁰. This is standard NCERT relation. Substitution & Calculation: 290 = x_A · 450 + (1 - x_A) · 150 . 290 = 450 x_A + 150 - 150 x_A . 140 = 300 x_A, x_A = 0.467 . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: What is the molarity of a solution prepared by dissolving 4 g of NaOH in water to make 200 mL of solution? (Molar mass of NaOH = 40 g/mol) These values define the system as per NCERT data. Formula: Moles = 4 / 40 = 0.1 mol. This is standard NCERT relation. Substitution & Calculation: Volume = 0.2 L. Molarity = 0.1 / 0.2 = 0.5 M. Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: Calculate the mole fraction of water in a solution containing 92 g of glycerol ( C₃H₈O₃ ) and 108 g of water. (Molar mass: C₃H₈O₃ = 92 g/mol, H₂O = 18 g/mol ) These values define the system as per NCERT data. Formula: Moles of glycerol = 92/92 = 1 mol. This is standard NCERT relation. Substitution & Calculation: Moles of water = 108/18 = 6 mol . Total moles = 1 + 6 = 7. Mole fraction of water = 6/7 = 0.857 . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: What is the EMF of the ll Zn(s) | Zn²⁺(0.1 M) || Cu²⁺(0.01 M) | Cu(s) at 298 K, given E_{Zn^{2+/Zn⁰ = -0.76 V and E_{Cu^{2+/Cu⁰ = 0.34 V ? These values define the system as per NCERT data. Formula: E_{ll⁰ = 0.34 - (-0.76) = 1.10 V, n = 2. This is standard NCERT relation. Substitution & Calculation: E_{ll = E_{ll⁰ - 0.059/2 log frac[Zn^{2+][Cu^{2+] = 1.10 - 0.059/2 log 0.1/0.01 . Q = 10, E_{ll = 1.10 - 0.0295 × 1 = 1.0705 V approx 1.07 V . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: What is the percentage of hydrogen in 0.18 g of a compound that produced 0.18 g of H₂O in combustion analysis? (Atomic masses: H = 1, O = 16) These values define the system as per NCERT data. Formula: Molar mass of H₂O = 18 g/mol. This is standard NCERT relation. Substitution & Calculation: Mass of H = 2 × 0.18/18 = 0.02 g. Percentage = 0.02 × 100/0.18 = 11.11% . Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: In 2Cu + O₂ -> 2CuO, how many grams of O₂ are needed to oxidize 127 g of Cu? (Atomic masses: Cu = 63.5, O = 16) These values define the system as per NCERT data. Formula: Moles of Cu = 127 / 63.5 = 2. This is standard NCERT relation. Substitution & Calculation: 2 moles Cu need 1 mole O₂ (32 g). Thus, 32 g. Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
Given: What is the molar conductivity of 0.00241 M acetic acid if its conductivity is 7.896 × 10⁻⁵ S cm⁻¹? These values define the system as per NCERT data. Formula: Lambda_m = kappa/c × 1000 = frac7.896 × 10⁻⁵⁰.00241 × 1000 = 32.76 S cm² mol^{-1 .. This is standard NCERT relation. Substitution & Calculation: Substituting values and simplifying step by step as per NCERT method. Result: The computed value matches expected outcome and confirms correct choice as per NCERT.
Ref: NCERT Chemistry Textbook for Class XI and XII, Chapter: Some Basic Concepts, Structure of Atom, Periodicity and relevant Chemistry topic, Topic: Mole concept and periodic trends.
