Class 12 Chemistry - Chapter Biomolecules NCERT Solutions | How do you explain the absence of aldehy

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

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?

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

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

What are nucleic acids? Mention their two important functions.

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

What are the different oxidation states exhibited by the lanthanoids?

How are polymers classified on the basis of structure?

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

Show how each of the following compounds can be converted to benzoic acid.

(i) Ethylbenzene        (ii) Acetophenone

(iii) Bromobenzene    (iv) Phenylethene (Styrene)

Discuss the general characteristics of Group 15 elements with reference to their electronic configuration, oxidation state, atomic size, ionisation enthalpy and electronegativity.

Calculate the half-life of a first order reaction from their rate constants given below:

(i) 200 s^-1

(ii) 2 min^-1

(iii) 4 years^-1

Explain the term copolymerisation and give two examples.

Discuss the main purpose of vulcanisation of rubber.

Give four uses of emulsions.

The molar conductivity of 0.025 mol L-1 methanoic acid is

46.1 S cm2 mol^-1.

Calculate its degree of dissociation and dissociation constant. Given λ⁰(H+)

= 349.6 S cm² mol^-1 and  λ⁰(HCOO^-) = 54.6 S cm² mol