1. What are the advantages of soapy detergents over soapless?

when we put on dirty cloths in detergent then due to chemical bonding
made up michell. one part of michell called head and another part is called tail. head contain Na and tail contain oH . and when we dropped dirty cloth on water then it has to be clean

2. If this element X combines with another element Y whose electronic configuration is 2, 8, 7 what will be the formula of the compound thus formed? State how did you arrive at this formula?

The element Y is Cl having electronic configuration 2,8,7
so to complete outer orbit and become stable it requires 1
electron So if it accepts 1 electron from Hydrogen (1) or Na having
electronic configuration (2,8,1) then the formula becomes

This will take place only if X is element having 1
electron in its outer orbit

3. How will you jug that the give organic compound is pure or not?

There are so many analytical method to know the organic
compound is pure or not such as find out the purity by
tlc,hptlc,hplc and also gavimetric methods are also there
such as limit test and ash of the compound as so on.....

5. Why all the concentration of chemical species are measured using water as solvent (for examole 1N NaOH means 40 g of NaOH in one litre of water)eventhough there are so many solvents available?

Water is a neutral solvent, doesn't react with NaOH or other
chemical species.
its density nearly about 1.0.

Some reagents may be prepare in so many solvents.

for example. 0.1N perchloric acid is prepared in glacial
actic acid in non aqueous titration.

Methanolic HCl(HCl in Methanol)or Hcl in Propanol etc

6. why in atomic mass electron is not include while proton and neutron include? although electron is a part of atom?

Electrons are moving around the orbit of the atom.According
to Heisenberg principle position and momentum(P) of a
moving particle cannot be determined simultaneously at one
instance. since mass is to be determined from the formula m
= P/v, where P is the momentum and v is the velocity of the
electron.even if we can able determine the velocity we
can't determine the momentum at that time. hence the mass
can't be determined.hence it is negleced from the atomic
mass calculation.

8. What is the valence of nitrogen?

Nitrogen has 5 valence electrons in an atom

9. In Einsteins mass energy relation e=mc2 for what is c used or why is light required for reactions. Because the reactions are with help of neutrons?

In This equation c is sed as a speed of light
In a chemical reactions most of the reaction are photolytic
reaction,which means bond breaks or formed with influence
of light.hence c is used in reaction