All Free Chemistry MCQs with Answers
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13,720 questions · page 677 of 686
13521. An Azeotropic mixture of two miscible liquids boils at a lower temperature than its components when:
- A. The system shows a negative deviation from Raoult's law.
- B. The system shows a positive deviation from Raoult's law.
- C. The system perfectly obeys Raoult's law
- D. Both (A) and (B)
Explanation: An azeotropic mixture is a combination of liquids that behave as a single substance with a consistent boiling point and consistent vapor…
Correct answer: The system shows a positive deviation from Raoult's law.- A. These parts of the body are warmer than the surroundings
- B. These parts of the body are cooler than the surroundings
- C. These parts of the body are constantly increasing and decreasing with the temperature
- D. None of the above options are correct
Explanation: Liquid crystalline substances are used to locate the viens, arteries, infections, and tumors.
Correct answer: These parts of the body are warmer than the surroundings- A. Diethyl ether
- B. Benzene
- C. Carbon disulphide
- D. Carbon tetrachloride
Explanation: When we compare the boiling points of different substances, we look at the intermolecular forces between their molecules.
Correct answer: Benzene- A. Both polar and non - polar molecules
- B. Non - polar molecules
- C. Polar molecules
- D. Statement is wrong
Explanation: London dispersion forces are present in all atoms and molecules, regardless of their size or composition.
Correct answer: Statement is wrong- A. +1, 0, -1
- B. 0, +1, +2
- C. -1, 0, +1
- D. 0, -1, +1
Explanation: The Magnetic Quantum Number (m) specifies the orientation in space of an orbital of a given energy (n) and shape (l).
Correct answer: -1, 0, +1- A. Apax-h
- B. AEA-h
- C. both (a) and (b)
- D. None
Explanation: The uncertainty principle arises from the wave-particle duality.A quite accurate measurement of one observable involves a relatively large…
Correct answer: both (a) and (b)- A. ±3
- B. ±1/2
- C. ±2
- D. Any positive number from 0 to -1
Explanation: n = 3, so possible l = 0, 1, 2For each l, m = -l to +lSo:l = 0 → m = 0l = 1 → m = -1, 0, +1l = 2 → m = -2, -1, 0, +1, +2✅ Range of m: -2…
Correct answer: ±2- A. 4
- B. 3
- C. 5
- D. 9
Explanation: This option is correct. The n=3 shell has three subshells corresponding to l=0, l=1, and l=2.
Correct answer: 3- A. 4
- B. 5
- C. 6
- D. 9
Explanation: 'n' is referred to as the principal quantum number and 'l' is the azimuthal quantum number.
Correct answer: 9- A. mvr = nh
- B. mvr = nh/2π
- C. mvr = n/2π
- D. mvr = nh/π
Explanation: The correct relationship for the angular momentum of an electron in a hydrogen atom according to Bohr's atomic theory is mvr = nh/2π…
Correct answer: mvr = nh/2π- A. 12C
- B. 15N
- C. 16O
- D. 32S
Explanation: The spin is a quality of particles, it tells us the angular momentum (½) of an electron of a substance.
Correct answer: 15N- A. 3
- B. 6
- C. 5
- D. 7
Explanation: The principal quantum number (n) determines the number of sublevels in a given energy level.
Correct answer: 5- A. 1.6
- B. 1.3
- C. 3.1
- D. 6.1
Explanation: The electronic configuration of chlorine is [Ne]3s23p5, indicating that the last electron is in the 3p subshell.
Correct answer: 3.1- A. 1
- B. 3
- C. 5
- D. 7
Explanation: For the sub-shell with n-4 and l=3, the number of orientations is 7. This is because the number of orientations is given by 2l + 1.
Correct answer: 7- A. Sec
- B. Sec-¹
- C. Mol dm-³sec-¹
- D. None of the above
Explanation: Because the units of the reaction rate are always moles per liter per second, the units of a first-order rate constant are reciprocal…
Correct answer: Sec-¹- A. Conductometry
- B. Polarimetry
- C. pH meter
- D. Volumetric analysis
Explanation: Volumetric analysis is specifically designed to measure concentration changes in a reaction over time, making it ideal for determining…
Correct answer: Volumetric analysis- A. Number of fruitful collisions per second
- B. Number or molecules taking part In a chemical reaction
- C. Number of total collisions per second
- D. All of the above
Explanation: The rate of a chemical reaction depends on the number of molecules or collisions taking part.
Correct answer: All of the above- A. Transition metal
- B. Alkali metal
- C. Alkaline earth metal
- D. None of above
Explanation: Group 1 elements, known as Alkali metals, fit the criteria of forming strong base salts and stable carbonates due to their low polarizing…
Correct answer: Alkali metal- A. They are less metallic in nature
- B. There is only one valency
- C. They do not having tightly packed structures
- D. They have high IE
Explanation: Alkali metals are soft because of their large atomic size and single valence electron, leading to weaker metallic bonds between atoms.
Correct answer: They do not having tightly packed structures- A. Na
- B. Ca
- C. Sr
- D. Li
Explanation: LiNO₃ → gives Li₂O + NO₂ (brown gas) + O₂.ng.
Correct answer: Li