Solutions — Chemistry STD 12 Science — Question

Give the electronic configuration of the following complexes on the basis of Crystal Field Splitting theory.
[CoF₆]^3-, [Fe(CN)₆]^4- and [Cu(NH₃)₆]²⁺

1. Answer the following questions briefly:

1. What are reducing sugars?
2. What is meant by denaturation of a protein?
3. How is oxygen replenished in our atmosphere?

2. Define enzymes.

What are the classification of proteins on the basis of molecular shape?

A colourless substance 'A' (C₆H₇N) is sparingly soluble in water and gives a water soluble compound 'B' on treating with mineral acid. On reacting with CHCl₃ and alcoholic potash 'A' produces an obnoxious smell due to the formation of compound 'C'. Reaction of 'A' with benzenesulphonyl chloride gives compound 'D' which is soluble in alkali. With NaNO₂ and HCl, 'A' forms compound 'E' which reacts with phenol in alkaline medium to give an orange dye 'F'. Identify compounds 'A' to 'F'.

Assign reasons for the following:

1. The enthalpies of atomisation of transition elements are high.
2. The transition metals and many of their compounds act as good catalyst.
3. From element to element the actinoid contraction is greater than the lanthanoid contraction.
4. The E⁰ value for the Mn³⁺/Mn²⁺ couple is much more positive than that for Cr³⁺/Cr²⁺.
5. Scandium (Z = 21) does not exhibit variable oxidation states and yet it is regarded as a transition element.

Explain the limitations of valence bound theory.

1. Answer the following questions briefly:

1. What are any two good sources of vitamin A?
2. What are nucleotides?
3. Give an example of simple lipids.

2. How are carbohydrates classified?

Match the complex ions given in Column I with the colours given in Column II and assign the correct code:

	Column I (Complex ion)		Column II (Colour)
a.	[Co(NH3)6]3+	1.	Violet
b.	[Ti(H2O)6]3+	2.	Green
c.	[Ni(H2O)6]2+	3.	Pale blue
d.	[Ni(H2O)4(en)]2+ (aq)	4.	Yellowish orange
		5.	Blue

Code:

1. A (1), B (2), C (4), D (5).
2. A (4), B (3), C (2), D (1).
3. A (3), B (2), C (4), D (1).
4. A (4), B (1), C (2), D (3).

Discuss aldol condensation in detail.

Match the items given in Column I with the type of solutions given in Column II.

	Column I		Column II
i.	Soda water	a.	A solution of gas in solid.
ii.	Sugar solution	b.	A solution of gas in gas.
iii.	German silver	c.	A solution of solid in liquid.
iv.	Air	d.	A solution of solid in solid.
v.	Hydrogen gas in palladium	e.	A solution of gas in liquid.
		f.	A solution of liquid in solid.