Coordination Compounds — Chemistry STD 12 Science — Question

1. Define the following terms:

1. Molarity.
2. Molal elevation constant(Kb).

2. A solution containing 15 g urea (molar mass = 60 g mol^–1) per litre of solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = 180 g mol^–1) in water. Calculate the mass of glucose present in one litre of its solution.

Classify carbohydrates and also give examples of each.

1. Account for the following:

1. Transition metals show variable oxidation states.
2. Zn, Cd and Hg are soft metals.
3. E^o value for the Mn³⁺/Mn²⁺ couple is highly

positive (+ 1·57 V) as compared to Cr³⁺/Cr²⁺.

2. Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

1. Calculate the freezing point of solution when 1.9 g of MgCl₂(M = 95 g mol^–1) was dissolved in 50 g of water, assuming MgCl₂ undergoes complete ionization. (K_f for water= 1.86 K kg mol^–1)
2.  

1. Out of 1 M glucose and 2 M glucose, which one has a higher boiling point and why?
2. What happens when the external pressure applied becomes more than the osmotic pressure of solution?

Match the property given in Column I with the element given in Column II.

	Column I (Property)		Column II (Element)
(i)	Lanthanoid which shows +4 oxidation state	(a)	Pm
(ii)	Lanthanoid which can show +2 oxidation state	(b)	Ce
(iii)	Radioactive lanthanoid	(c)	Lu
(iv)	Lanthanoid which has 4f7 electronic configuration in +3 oxidation state	(d)	Eu
(v)	Lanthanoid which has 4f14 electronic configuration in +3 oxidation state	(e)	Gd
		(f)	Dy

Primary alkyl halide C4H9Br (a) reacted with alcoholic KOH to give compound (b). Compound (b) is reacted with HBr to give (c) which is an isomer of (a). When (a) is reacted with sodium metal it gives compound (d), C8H18 which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (a) and write the equations for all the reactions.

Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.

Rate constant for a first order reaction has been found to be 2.54 × 10^-3s^-1. Calculate its three-fourth life.

Match the items given in Column I and Column II.

	Column I		Column II
i.	Saturated solution	a.	Solution having same osmotic pressure at a given temperature as that of given solution.
ii.	Binary solution	b.	A solution whose osmotic pressure is less than that of another.
iii.	Isotonic solution	c.	Solution with two components.
iv.	Hypotonic solution	d.	A solution which contains maximum amount of solute that can be dissolved in a given amount of solvent at a given temperature.
v.	Solid solution	e.	A solution whose osmotic pressure is more than that of another.
vi	Hypertonic solution	f.	A solution in solid phase.

What is called a battery? Explain its characteristics and describe dry cell and mercury cell.