Science (English Medium) इयत्ता १२ - CBSE Important Questions for Chemistry

Value of Henry's constant K_H ______.

Which one of the following would feel attraction when placed in magnetic field: Co²⁺, Ag⁺, Ti⁴⁺, Zn²⁺ 

Given below are two statements labelled as Assertion (A) and Reason (R).

Assertion: Magnetic moment values of actinides are lesser than the theoretically predicted values.

Reason: Actinide elements are strongly paramagnetic.

Select the most appropriate answer from the options given below:

State Henry’s law and explain why are the tanks used by scuba divers filled with air diluted with helium (11.7% helium, 56.2% nitrogen and 32.1% oxygen)?

Assume that argon exerts a partial pressure of 6 bar. Calculate the solubility of argon gas in water. (Given Henry’s law constant for argon dissolved in water, K_H = 40 k bar)

Read the passage carefully and answer the questions that follow:

Assuming the melting point of pure water as 0°C, answer the following questions:

1. One temperature in the second set of results does not fit the pattern. Which temperature is that? Justify your answer.
2. Why did Henna collect two sets of results?
3. In place of NaCl, if Henna had used glucose, what would have been the melting point of the solution with 0.6 g glucose in it?
   OR
   What is the predicted melting point if 1.2 g of salt is added to 10 mL of water? Justify your answer.

Assertion (A) : Osmotic pressure is a colligative property.

Reason (R) : Osmotic pressure is proportional to the molality.

An azeotropic mixture of two liquids will have a boiling point lower than either of the two liquids when it ______.

Assertion (A): Elevation in boiling point is a colligative property.

Reason (R): The lowering of vapour pressure of solution causes elevation in boiling point.

Solubility of gas in liquid decreases with increase in ______.

Assertion (A): The enthalpy of mixing Δ_mix H is equal to zero for an ideal solution.

Reason (R): For an ideal solution the interaction between solute and solvent molecules is stronger than the interactions between solute-solute or solvent-solvent molecules.

1 mole of liquid A and 2 moles of liquid B make a solution having a total vapour pressure of 40 torr. The vapour pressure of pure A and pure B are 45 torr and 30 torr, respectively. The above solution ______.

If the molality of a dilute solution is doubled, the value of the molal elevation constant (K_b) will be ______.

Which of the following aqueous solution will have the highest boiling point?

Out of the following 1.0 M aqueous solution, which one will show the largest freezing point depression?

Which of the following is not correct?

In which of the following solvents, the \[\ce{C4H8NH3+X–}\] is soluble?

What is the effect of temperature on the solubility of glucose in water?

Ibrahim collected 10 mL each of fresh water and ocean water. He observed that one sample labeled “P” froze at 0° C while the other “Q” at -1.3° C. Ibrahim forgot which of the two, “P” or “Q” was ocean water. Help him identify which container contains ocean water, giving rationalization for your answer.

Calculate Van't Hoff factor for an aqueous solution of K₃ [Fe(CN)₆] if the degree of dissociation (α) is 0.852. What will be boiling point of this solution if its concentration is 1 molal? (Kb = 0.52 K kg/mol)