Which transition metal forms a complex with CO that has maximum carbonyl stretching frequency?

The correct answer is C: Mn. Manganese with lower electron density shows weaker back-bonding, resulting in higher CO stretching frequency. The order is Mn > Co > Fe > Ni based on back-bonding strength.

The solubility of alkaline earth metal hydroxides increases down the group with the exception of:

The correct answer is D: Be(OH)₂ is least soluble. Be(OH)₂ is amphoteric and has low solubility. Generally, solubility increases from Mg to Ba, but Be(OH)₂ doesn't follow this trend due to its amphoteric nature.

A galvanic cell is constructed using Zn/Zn²⁺ (E° = -0.76 V) and Cu/Cu²⁺ (E° = +0.34 V) electrodes. What is the standard cell potential?

The correct answer is B: 1.10 V. E°cell = E°cathode - E°anode = 0.34 - (-0.76) = 0.34 + 0.76 = 1.10 V. Cu²⁺/Cu is cathode (reduction), Zn²⁺/Zn is anode (oxidation).

The cell potential of a galvanic cell decreases during operation because:

The correct answer is B: The concentration of products increases. As the reaction proceeds, product concentrations increase while reactant concentrations decrease, reducing the driving force according to Nernst equation: E = E° - (0.059/n)log(Q).

Which statement about nitrogen oxides is incorrect?

The correct answer is C: N₂O₄ is blue gas. N₂O₄ is colorless gas, not blue. NO is colorless, NO₂ is brown/reddish-brown, and N₂O is indeed called laughing gas.