Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
For any compound to be water soluble, it should develop dipoles (partial negative and partial positive charges) at the two ends of compound. The development of charges results in the formation of hydrogen bond between the water molecule and the compound. The development of charges at two ends is due to the difference in the electronegativity between two atoms. The atom with higher electronegativity will acquire negative charge while the atom with lower electronegativity will acquire positive charge. A glucose molecule contains five –OH (highly electronegative) groups while a sucrose molecule contains eight −OH groups. Thus, glucose and sucrose undergo extensive H-bonding with water. Hence, these are soluble in water.
But cyclohexane and benzene do not contain −OH groups. They contain only carbon and hydrogen atoms, as a result the dipole developed is very weak in nature and hence the hydrogen bond formed is not strong. Hence, they cannot undergo H-bonding with water and thus are insoluble in water.
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?
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
Why is glass considered a super cooled liquid?
Why is the ester hydrolysis slow in the beginning and becomes faster after sometime?
Why are solids rigid?
Which one of the following has the highest dipole moment?
(i) CH2Cl2
(ii) CHCl3
(iii) CCl4
How are colloids classified on the basis of
(i) Physical states of components
(ii) Nature of dispersion medium and
(iii) Interaction between dispersed phase and dispersion medium?
Write chemical reaction of aniline with benzoyl chloride and write the name of the product obtained.
The hexaquo manganese(II) ion contains five unpaired electrons, while the hexacyanoion contains only one unpaired electron. Explain using Crystal Field Theory.
Considering the parameters such as bond dissociation enthalpy, electron gain enthalpy and hydration enthalpy, compare the oxidising power of F2 and Cl2.
Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.
(i) Methanal (ii) 2-Methylpentanal
(iii) Benzaldehyde (iv) Benzophenone
(v) Cyclohexanone (vi) 1-Phenylpropanone
(vii) Phenylacetaldehyde (viii) Butan-1-ol
(ix) 2, 2-Dimethylbutanal
How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?
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