Chemistry Test - 33

Colligative properties depend on the number of solute particles and are independent of the nature of the solute. Osmotic pressure, boiling point elevation, and freezing point depression are examples.

(A) is correct because Raoult's law applies only on ideal solutions

(B) is correct as Raoult’s law states that the vapor pressure of a solvent in a solution is directly proportional to the mole fraction of the solvent.

(C) is incorrect because Raoult’s law is not strictly limited to non-volatile solutes, and it can apply to solutions with volatile solutes, though deviations may occur for highly volatile solutes.

(D) is incorrect because Raoult's law holds true primarily for ideal solutions, where there is no deviation in behavior between the solute and solvent.

Colligative properties depend on the number of solute particles, ideal solutions have similar intermolecular forces, and osmosis is the movement of solvent from low to high concentration.

(A) is correct because the molal freezing point depression constant is a property of the solvent and varies depending on the solvent.

(B) is incorrect because the molal freezing point depression constant is not the same for all solvents; it is specific to each solvent.

(C) is correct because the molal freezing point depression constant is used to calculate the depression in freezing point, which depends on the concentration of the solute.

(D) is incorrect because K_f is a solvent-specific constant, independent of the amount or identity of the solute.

ilver in the form of Ag⁺ is colourless. For transition metal ions to exhibit color, their metal ions must have incompletely filled (n-1)d orbitals.

Ag⁺ =4d¹⁰,5s⁰

Ag⁺ has completely filled d orbitals hence is colourless.

Zn²⁺ has completely filled d-orbitals and there are no vacant d-orbitals for the transition of electrons, hence it is colourless.

Till d⁵ unpaired electron are increasing so maximum bonding as unpaired electron take part in bonding. So melting point increases till d⁵ then start decreasing due to pairing which decreases metallic bond strength and thus melting point.

Cr(24) = [Ar]3d54s1

Since (CO) is strong ligand, in Cr(CO)₆ none of the electron is unpaired. Therefore ‘spin only’ magnetic moment is zero.

The acetylacetonate (acac) forms six membered ring as follows:

Correct Answer : a

Explanation : NO in brown ring complex has +1 oxidation state.

Let oxidation state of Fe be x.

Since the overall charge on the coordination sphere, [Fe(H2O)5NO+]  is +2, the sum of oxidation states of all elements in it should be equal to +2.

Therefore, x+1=+2

or, x=+1 

Hence, the oxidation state of iron in the brown ring complex is +1.