Posts Tagged ‘chemistry’

How was CBSE Chemistry Exam 2016?

How was the CBSE Chemistry exam 2016?

It was reported by various agencies that this year’s (2016) exam was the toughest compared to last 5 years question paper. Is it true? Was the question paper really a hard nut?IMG-20160310-WA0005

How much do you expect in   CBSE Chemistry theory paper?

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Be the first to comment - What do you think?  Posted by admin - March 9, 2016 at 1:13 pm

Categories: AISSCE CHEMISTRY   Tags: , , ,

Advantages of synthetic detergents over soaps

Synthetic detergents have several advantages over soaps.

  1. Synthetic detergents can be used even in hard water whereas some of the soap gets wasted if the water is hard.
  2. Synthetic detergents can be used even in acidic medium as they are the salts of strong acids and are not decomposed in acidic medium.
  3. Synthetic detergents have a stronger cleansing action than soaps.
  4. Synthetic detergents  are more soluble in water than soaps.
  5. Synthetic detergents are prepared from the hydrocarbons obtained from petroleum. This saves vegetable oils which are otherwise used for making soaps

Be the first to comment - What do you think?  Posted by admin - February 12, 2014 at 9:06 pm

Categories: AISSCE CHEMISTRY, CBSE Chemistry, CHEMISTRY IN EVERYDAY LIFE   Tags: , , , ,

Memorise Periodic Table using Mnemonics

Group 1>H(Hydrogen)ele(Lithium)n(Sodium) K(Potassium)abr(Rubidium) Se(Cesium)faraar(Francium)
= Helen kabr se faraar
Group 2>Be(Beryllium)ta mange(Magnesium) Car(Calcium) scooter(Strontium) Baap(Barium)Roye(Rubidium)
=Beta maange car scooter , baap roye
Group 13>B(Boron)al(Aluminium) Ga(Gallium)ngadhar In(Indium)dian Ti(Thallium)lak
==Bal Gangadhar Indian Tilak

Group 14>C(Carbon)ollege student(Silicon) ge(Germanium)t some(Sn=Tin) prob(Pb=Lead)lem
==College student get some problem
Group 15>N(Nitrogen)ews p(Phosphorus)aper Aaj (Arsenic) sab(Sb=Antimony) bi(Bismuth)kega
===News paper aaj sab bikega
Group 16>O(Oxygen)s(Suplhur) se(Selenium) te(Tellurium)po(Polonium) ( Os = Uss , Tepo is a word meaning to press)
===Os se tepo
Group 17>F(Flourine)ir Kal(Chlorine) bahar(Bromium) aayi(I = Iodine)
====Fir kal bahar aayi
Group 18>Hai (Helium) Na(Neon)na Aaj(Argon)  Ka (Krypton)  Zinda(Xenon)  Raja(Radium)
====Hai Nana aaj ka Zinda raja

The Hydrogen group

Hi Lila Ne Kiya Rab se fariyaad

Hydrogen(H), Lithium(Li), Sodium(Na), Pottassium(K), Rubidium(Rb), Cesium(Cs), Francium(Fr)

 

Be the first to comment - What do you think?  Posted by admin - February 26, 2013 at 12:07 pm

Categories: CBSE Chemistry   Tags: , , , , , , ,

CBSE Class 12 Chemistry Sample Paper – HALOALKANES AND HALOARENES

MM : 25                                       TIME : 45 MIN.
1. Give IUPAC names of the following compounds:
(a) CH2=CH-CH – C=CH2
C2H5 Cl
(b) CH3-CH2-CH-C6H5Br
CH3
2. Write the structure of the following organic halogen compounds :
(a) 4-tert-butyl-3-iodoheptane
(b) 2-(2-chlorophenyl)-1-iodooctane
3. Explain the following reaction:
(a) Friedel craft alkylation reaction.
(b) Wurtz reaction
(c) Sandmeyer’s reaction
(d) Finkelstein reaction
4. Convert the following:
(a) Ethane to bromoethene
(b) But-1-ene to but-2-ene
(c) Propene to propyne
(d) Benzyl alcohol to 2-phenylethanoic acid
(e) Aniline to chlorobenzene
5. Explain Markownikoff’s rule with example.
6. Explain the following
(a) Vinyl chloride is hydrolysed more slowly than ethyl chloride
(b) The treatment of alkyl chloride with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH , alkenes are the major products.
7. Distinguish between C2H5Br and C6H5Br through chemical test .
8. What are Enantiomers and Racemic mixtures ?
9. Predict the order of reactivity of the following compounds in SN1 reaction C6H5CH2Br , C6H5CH(C6H5)Br , C6H5CH(CH3)Br , C6H5C(CH3)(C6H5)Br
10. What is chemical name of D.D.T ? How it is prepared ?

 

Be the first to comment - What do you think?  Posted by admin - February 21, 2013 at 1:29 pm

Categories: AISSCE CHEMISTRY, CBSE Chemistry, Chemistry Model Papers   Tags: , , , , , , ,

CBSE Class 12 Chemistry Test – Organic Compunds containing Nitrogen

MM : 25                                                                                        TIME : 45min.
1. Write a chemical equation each to illustrate the following reaction:
(a) Carbylamine reaction
(b) Hofmann – bromamide reaction
(c) Gabriel phthalimide synthesis
(d) Balz – Schiemann reaction
(e) Diazotisation reaction
2. Separate primary secondary and tertiary amines on the basis of Hinsberg’s method.
3. Convert the following :
(a) Aniline into fluorobenzene
(b) Toluene into p-toluic acid.
(c) Aniline to sulphanilic acid .
4. Why are amines are less acidic than alcohols of comparable molecular masses?
5. How is basic strength of aromatic amines affected by the presence of electron releasing group on the benzene ring?
6. Explain why Amino group in ethylamine is basic but not in acetamide ?
7. Out of aliphatic and aromatic amines which one is soluble in water and why?
8. Give one chemical test to distinguish between benzyl amine and anilne.
9. What happens when ethylamine is treated with CHCl3 in the presence of ethanolic KOH.
10. Discuss the importance of pH in coupling reaction.

 

Be the first to comment - What do you think?  Posted by admin - at 1:17 pm

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