Selected MCQ

Current Question
The oxidation state of chromium in (Cr_2O_7^{2-}) is:
  • A. +3
  • B. +4
  • C. +6
  • D. +7
Correct Answer: C
Explanation:
Letting Cr be (x), (2x+7(-2)=-2) gives (x=+6).
Related Question 1
Which species has highest oxidation state?
  • A. MnO₂
  • B. Mn₂O₇
  • C. MnO
  • D. Mn₃O₄
Correct Answer: B
Explanation:
Mn in Mn₂O₇ is +7.
Related Question 2
In a Hilbert space formulation of quantum mechanics, physical states are represented by:
  • A. Real numbers
  • B. Vectors up to a global phase
  • C. Scalars only
  • D. Matrices only
Correct Answer: B
Explanation:
States are rays in Hilbert space, invariant under global phase.
Related Question 3
Which state of matter has long-range order but flows?
  • A. Solid
  • B. Liquid crystal
  • C. Gas
  • D. Plasma
Correct Answer: B
Explanation:
Liquid crystals combine order and fluidity.
Related Question 4
Which principle states particles are indistinguishable?
  • A. Pauli principle
  • B. Superposition principle
  • C. Indistinguishability principle
  • D. Correspondence principle
Correct Answer: C
Explanation:
Quantum particles of same type are identical.
Related Question 5
Which state has fixed volume but no shape?
  • A. Solid
  • B. Liquid
  • C. Gas
  • D. Plasma
Correct Answer: B
Explanation:
Liquids have definite volume.