12. Borax is used as a buffer since:
(a)its aqueous sol. contains equal amount of weak acid and its salt
(b) it is easily available
(c) its aq sol contains equal amt of strong acid and its salt
(d) statement that it is a buffer is wrong.
1.Gas that strikes in thundering of light is:
(a) CO
(b) NO
(c) CO2
(d) H2
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13 Answers
113. Carbogen is:
(a) mixture of CO + CO2
(b) mixture of O2+CO2
(c) pure form of carbon
(d) unsaturated organic compound
14. The number of P-O-P BONDS IN cyclic metaphosporic acid is:
(A) 0
(B) 2
(C) 3
(D) 4
1Q.1) the gas is NO.
Q.2) Aqueous borax acts as a strong buffer.
[B4O7]2- + H2O → 2[ B(OH)4 ]-(CONJUGATE BASE) + 2B(OH)3(WEAK ACID)
here their concentration in the reaction is 1:1
Q.3)Carbogen refers to the mixture of CO2 and O2 (IN ANY PROPORTION)
Q.4)I don't know abt this acid, but it might be reffering to cyclic metadiphosphate ion.
so,it might be 2.
Q.5)A. By reaction of Mg3N2 with D2O.
B. BY USING CYANOHYDRIDOBORATE AS SELECTIVE REDUCING AGENT
16.( Me)2SiCl2 on hydrolysis will produce:
(a).(Me)2Si(OH)2
(b)(Me)2Si=O
(c) [-O-(Me)2Si-O-]n
(d) Me2SiCl(OH)
1it will give : a) (Me)2Si(OH)2.
this is because alkyl substituted chloro silanes on hydrolysis gives alkyl substituted hydroxyls,which on polymerisation gives silicones.
1then it might be referring to polymerised state i.e. silicones.
c) represents silicones.
1normally, it should be a). if a) is not given, then c).
but thats just my own opinion
17. In graphite additional electrons are :
(a) localised on each C-atom
(b) localised on every third C-atom
(c) present in anti-bonding orbital
(d) delocalised forming extended pi- bonding system
1Q.7) the additional e-s r delocalised forming extended pi-bonding system.
because these electrons in the remaining p-orbitals r used to form a pi-bond and each C-atom shares pi-bond with its neighbours and pi-electrons r delocalised.this increases the electrical conductivity of graphite