85) When potassium dichromate crystals are heated with conc. HCl:

86) Arrange in the decreasing order of standard electrode potentials:

87) Sodium peroxide, which is a yellow solid, when exposed to air becomes white due to formation of:

88) Which of the following alkali metals has the biggest tendency for the half reaction, M (g) → M⁺ (aq) + e⁻?

89) Which one of the following on heating will not give CO₂?