How does the presence of double bonds in rubber molecules influence their structure and reactivity?
Natural rubber is a linear cis-1,4- polyisoprene in which double bonds are present between C2 and C3 of isoprene units.
The cis configuration about double bonds does not allows the chains to come closer for effective intermolecular attraction due to weak intermolecular attractions. Therefore, the natural rubber has coiled structure and shows elasticity and is non crystalline.
On the other hand, all trans configurations occur in gutta-percha (synthetic rubber) which is trans-polyisoprene. These zig-zag chains pack more closely in gutta-percha and hence it is highly crystalline, non elastic, more hard and brittle than rubber.
Write the names and structures of the monomers of the following polymers:
(i) Buna-S (ii) Buna-N
(iii) Dacron (iv) Neoprene
What is a biodegradable polymer? Give an example of a biodegradable aliphatic polyester.
Arrange the following polymers in increasing order of their intermolecular forces.
(i) Nylon 6, 6, Buna-S, Polythene.
(ii) Nylon 6, Neoprene, Polyvinyl chloride.
Explain the difference between Buna-N and Buna-S.
How are polymers classified on the basis of structure?
Define thermoplastics and thermosetting polymers with two examples of each.
Explain the term copolymerisation and give two examples.
Write the monomers used for getting the following polymers. (i) Polyvinyl chloride (ii) Teflon (iii) Bakelite
How do you explain the functionality of a monomer?
Identify the monomer in the following polymeric structures.
(i)
(ii)
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?
Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
Calculate the mass percentage of aspirin (C9H8O4) in acetonitrile (CH3CN) when 6.5 g of C9H8O4 is dissolved in 450 g of acetonitrile (CH3CN).
Write the conditions to maximize the yield of H2SO4 by Contact process.
FeSO4 solution mixed with (NH4)2SO4 solution in 1:1 molar ratio gives the test of Fe2+ ion but CuSO4 solution mixed with aqueous ammonia in 1:4 molar ratio does not give the test of Cu2+ ion. Explain why?
Determine the osmotic pressure of a solution prepared by dissolving 25 mg of K2SO4 in 2 liter of water at 25° C, assuming that it is completely dissociated.
Give the disproportionation reaction of H3PO3.
A compound forms hexagonal close-packed structure. What is the total number of voids in 0.5 mol of it? How many of these are tetrahedral voids?
Why are vitamin A and vitamin C essential to us? Give their important sources.
Calculate the standard cell potentials of galvanic cells in which the following reactions take place:
(i) 2Cr(s) + 3Cd2+(aq) → 2Cr3+(aq) + 3Cd
(ii) Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)
Calculate the ΔrGø¸ and equilibrium constant of the reactions.
What are enzymes?
Indicate the types of isomerism exhibited by the following complexes and draw the structures for these isomers:
(i) K[Cr(H2O)2(C2O4)2
(ii) [Co(en)3]Cl3
(iii) [Co(NH3)5(NO2)](NO3)2
(iv) [Pt(NH3)(H2O)Cl2]