Solutions — Chemistry STD 12 Science — Question

Answer the following question:
Calculate the molality of a sulphuric acid solution in which the mole fraction of water is 0.85.

Attempt any five of the following:
(a) Define native state in reference to proteins.
(b) Define the following terms:
    a. Polysaccharides
    b. Nucleotides
(c) Deficiency of which vitamin causes scurvy?
(d) What happens when D-glucose is treated with the following? Give equations to support your answer.
    a. HI
    b. HNO₃
(e) Name the disaccharide which on hydrolysis gives glucose and galactose.
(f) Write the products obtained after hydrolysis of lactose.
(g) Give the reaction of glucose with hydrogen cyanide. Presence of which group is confirmed by this reaction?

Match the coordination compounds given in Column I with the central metal atoms given in Column II and assign the correct code:

	Column I (Coordination Compound)		Column II (Central metal atom)
a.	Chlorophyll	1.	Rhodium
b.	Blood pigment	2.	Cobalt
c.	Wilkinson catalyst	3.	Calcium
d.	Vitamin B12	4.	Iron
		5.	Magnesium

Code:

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

Expian the basic properties of amines.

Match the complex ions given in Column I with the hybridisation and number of unpaired electrons given in Column II and assign the correct code:

	Column I (Complex ion)		Column II (Hybridisation, number of unpaired electrons)
a.	[Cr(H2O)6]3+	1.	dsp2, 1
b.	[Co(CN)4]2-	2.	sp3d2, 5
c.	[Ni(NH3)6]2+	3.	d2sp3, 3
d.	[MnF6]4-	4.	sp3, 4
		5.	sp3d2, 2

Code:

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

(a) What type of protein is present in keratin?
(b) Write the reactions showing the presence of following in the open structure of glucose:
   i. an aldehyde group
  ii. a primary alcohol
(c) What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?
(d) Amino acids show amphoteric behaviour. Why?
(e) What are a Amino Acids? Give examples.
(f) a. How can you explain the absence of an aldehyde group in the pentaacetate of D-glucose?
    b. Name the bases present in RNA. Which one of these is not present in DNA?
(g) Which monosaccharide units are present in starch, cellulose and glycogen and which linkages link these units?

Write short notes on the following :
(i) Kolbe's electrolytic reaction
(ii) Hell-Volhard-Zelinsky reaction
(iii) Esterification reaction
(iv) Decarboxylation reaction(v) Hunds-Diecker reaction

What do you understand by rate of a reaction? What factors affect the rate of a reaction? Discuss.