Class 12 Chemistry - Chapter Biomolecules NCERT Solutions | What are nucleic acids? Mention their tw

What happens when D-glucose is treated with the following reagents? (i)HI (ii)Bromine water (iii)HNO₃

How do you explain the absence of aldehyde group in the pentaacetate of D-glucose?

Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.

The melting points and solubility in water of amino acids are generally higher than that of the corresponding halo acids. Explain.

Define the following as related to proteins 

(i) Peptide linkage  (ii) Primary structure  (iii) Denaturation.

What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?

Enumerate the reactions of D-glucose which cannot be explained by its open chain structure.

The two strands in DNA are not identical but are complementary. Explain.

Where does the water present in the egg go after boiling the egg?

How do you explain the amphoteric behaviour of amino acids?

For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt (III) chloride

(ii) Potassium tetracyanonickelate(II)

(iii) Tris(ethane-1,2-diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanoferrate(II)

(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N

(ii) Write IUPAC names of all the isomers.

(iii) What type of isomerism is exhibited by different pairs of amines?

Why are solids rigid?

Write any two characteristics of Chemisorption.

Write the structures of the following compounds.

(i) α-Methoxypropionaldehyde

(ii) 3-Hydroxybutanal

(iii) 2-Hydroxycyclopentane carbaldehyde

(iv) 4-Oxopentanal

(v) Di-sec-butyl ketone

(vi) 4-Fluoroacetophenone

Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?

Why are pentahalides more covalent than trihalides?

Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?

Write structures of the following compounds:

(i) 2-Chloro-3-methylpentane

(ii) 1-Chloro-4-ethylcyclohexane

(iii) 4-tert. Butyl-3-iodoheptane

(iv) 1,4-Dibromobut-2-ene

(v) 1-Bromo-4-sec. butyl-2-methylbenzene

Write structures of the products of the following reactions:

(i)

(ii)

(iii)

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

Analysis shows that nickel oxide has the formula Ni_0.98 O_1.00. What fractions of nickel exist as Ni²⁺and Ni³⁺ions?

Comment on the nature of two S-O bonds formed in SO₂ molecule. Are the two S-O bonds in this molecule equal?

From the rate expression for the following reactions, determine their order of reaction and the dimensions of the rate constants.

(i) 3 NO(g) → N₂O(g)  Rate = k[NO]²

(ii) H₂O₂ (aq) + 3 I ^- (aq) + 2 H⁺→ 2 H₂O (l) +  I₃^-  Rate = k[H₂O₂][I ^- ]

(iii) CH₃CHO(g)  → CH₄(g) + CO(g)  Rate = k [CH₃CHO]^3/2

(iv) C₂H₅Cl(g) → C₂H₄(g) + HCl(g)  Rate = k [C₂H₅Cl]

Give four uses of emulsions.

Sea is the greatest source of some halogens. Comment.

Write the structures of the following organic halogen compounds.

(i) 2-Chloro-3-methylpentane

(ii) p-Bromochlorobenzene

(iii) 1-Chloro-4-ethylcyclohexane

(iv) 2-(2-Chlorophenyl)-1-iodooctane

(v) Perfluorobenzene

(vi) 4-tert-Butyl-3-iodoheptane

(vii) 1-Bromo-4-sec-butyl-2-methylbenzene

(viii) 1,4-Dibromobut-2-ene

Why do soaps not work in hard water?

A compound is formed by two elements M and N. The element N forms ccp and atoms of M occupy 1/3^rd of tetrahedral voids. What is the formula of the compound?