Some doubts in Chemistry

1) A chemical contained in tea is also contained in the bark of a tree. It is used for making ink removers. that chemical is
a) tannic acid b)oxalic acid
c)carbonate d) cellulose

2)which of the following cannot dissolve in carbon disulphide?
a) rubber b) oil and fats
c)sulphur, bromine and iodine
d) sugar and proteins

3)a very pure form of carbon dioxide can be obtained from
a) formic acid b)sodium oxalate
c) sodium hexacyanoferrate
d) nickel tetracarbonyl

4)German silver is made of 60% copper along with
a) nickel and zinc
b) cobalt and iron
c)chromium and lead
d)silver and lithium

5) which of the following is incoorect regarding boron nitride?
a) it is chemically unreactive
b) its structure is like that of diamond and hence hard
c)it can be melted under pressure at a very high temp of 3000°C
d)it has magnetic properties

6)the most common element on earts crust is oxygen.
the second most common elemant is
a) iron b)silicon
c)copper d) aluminium

7)Which of the following allotropes of tin does not exist
a)grey tin b) brown tin
c)white tin d)rhombic tin

8) which of the following is not a urease inhibitor?
a) phenols b) quinones
c) benzene d) benzoquinones

9)which of the following is false
a) terylene is mainly dyed with disperse dyes
b) cotton can be dirctly syed with malachite green
c)nylon can be dyed with acid dyes
d) polyacronitrile can be dyed with basic dyes

10) emulsions of polyvinyl acetate are ued in
a) fire crackers
b)crayons
c) polishes
d)latex paints