Class 12 Chemistry - Chapter Biomolecules NCERT Solutions | The two strands in DNA are not identical

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.

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

An element with molar mass 2.7 x 10^-2kg mol^-1 forms a cubic unit cell with edge length 405 pm. If its density is 2.7 x 10³ kg m^-3, what is the nature of the cubic unit cell?

Which one of the following does not exist?

(i) XeOF₄

(ii) NeF₂

(iii) XeF₂

(iv) XeF₆

Show how will you synthesize:

(i) 1-phenylethanol from a suitable alkene.

(ii) cyclohexylmethanol using an alkyl halide by an S_N2 reaction.

(iii) pentan-1-ol using a suitable alkyl halide?

Why is use of aspartame limited to cold foods and drinks?

For a first order reaction, show that time required for 99% completion is twice the time required for the completion of 90% of reaction.

Why is the ester hydrolysis slow in the beginning and becomes faster after sometime?

Predict the number of unpaired electrons in the square planar [Pt(CN)₄]^2- ion.

'Stability of a crystal is reflected in themagnitude of its melting point'. Comment. Collect melting points of solid water, ethyl alcohol, diethyl ether and methane from a data book. What can you say about the intermolecular forces between these molecules?

Give equations of the following reactions:

(i) Oxidation of propan-1-ol with alkaline KMnO₄ solution.

(ii) Bromine in CS₂ with phenol.

(iii) Dilute HNO₃ with phenol.

(iv) Treating phenol with chloroform in presence of aqueous NaOH.

Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?