1 Ionic Equilibrium
Precipitation takes place when the product of concentration of ions :
1) is less than their solubility product 2) is negligible 3) equals their solubility product 4) exceeds their solubility product.
Solution Precipitation occurs when ionic product > solubility.
2 Coordination Compounds
One mole of the complex compound Co(NH3)5Cl3 gives three moles of ions on dissolution in water. One mole of the same complex reacts with two moles of AgNO3 solution to yield two moles of AgCl(s). The structure of complex is:
1) $$[Co(NH_{3})_{4}Cl]Cl_{2}.NH_{3}$$ 2) $$[Co(NH_{3})_{5}Cl]Cl_{2}$$ 3) $$[Co(NH_{3})_{3}Cl_{3}]2.NH_{3}$$ 4) $$[Co(NH_{3})_{4}Cl_{2}]Cl.NH_{3}$$
$$Co(NH_{3})_{5}Cl_{3}$$ gives three ions- one complex ion and two chloride ion. Which is confirmed by reaction with silver nitrate. $$2AgNO_3+2Cl^-\rightarrow 2AgCl$$ So, compound is $$[Co(NH_{3})_{5}Cl]Cl_{2}$$.
3 D and F Block Elements
Which is wrongly matched ?
1) Duralumin-Al+Cu+Mg+Mn 2) Alnico-Fe+Al+Ni+Co 3) German silver-Cu+Zn+Ni 4) Monel metal-Cu+Zn+Sn
4 Environmental Chemistry
Silk and woolen clothes are often damaged by
1) Flies
2) Insects
3) Bacteria
4) Animals
Because insects have the ability to digest silk and wool. Examples of insects that damage the clothes are-silverfish, cockroach, moth etc.
5 Aldehydes Ketones and Carboxylic Acids
Aliphatic amide on treatment with HNO2 gives the gas 1) CO2 2) N2 3) O2 4) H2
Aliphatic amide on treatment with $$HNO_2$$ gives $$N_2$$ gas. $$RCONH_2 + HONO \rightarrow RCOOH + N_2 + H_2O$$.
6 General Principles & Process of Isolation of Metals
$$Ag_2S + NaCN \longrightarrow (A), (A) + Zn \longrightarrow (B)$$ (B) is a metal. Hence (A) and (B) are:
1) $$Na_2[Zn(CN)_4],Zn$$ 2) $$Na_2[Ag(CN)_2],Ag$$ 3) $$Na_2[Ag(CN)_4],Ag$$ 4) $$Na_3[Ag(CN)_4],Ag$$
7 Hydrocarbons
An alkyl bromide, RBr of molecular weight 151 is the exclusive product of bromination of which hydrocarbon?
1) Dodecane 2) 2,2 - dimethylpropane 3) 2,2 - dimethylhexane 4) 2,2,3 - trimethylheptane
SOLUTION
Molecular weight of RBr=151
Molecular weight of Br=80
∴ Molecular weight of −R=151−80=71
If we consider 2,2−dimethylpropane the molecular formula is C5H12 .
After bromination, C5H11Br
∴ Molecular weight of C5H11=60+11=71
8 Biomolecules
Ribose is an example of a/an: 1) aldopentose. 2) ketohexose. 3) aldohexose. 4) disaccharide.
9 Basic Principles of Organic Chemistry
The maximum number of isomers (including stereoisomers) that are possible on monochlorination of the following compound, is 1) 4 2) 7 3) 6 4) 8
Three chiral carbon ∴ 23 = 8 isomers
10 S – Block Elements
Sodium metal cannot be stored in
1) toluene
2) alcohol
3) kerosene
4) benzene
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