(Each and every questions are not answered, they will be added soon and in any chaos please comment)
Solution:
Decomposition
of Hydrogen Peroxide is not an equilibrium reaction. Hence, though the reaction
is highly exothermic the action of lowering the temperature won’t give any
result. (C is incorrect)
Adding
water is totally irreverent as it don’t have any effect on either oxygen
production or rate.
Catalysis
have effect on the rate of reaction only, the yield of product is independent
of the catalysis. In the graph, the peak of Y is higher than that of X, means
that the yield of Y is more and catalysis can’t do that. (D is incorrect).
But,
to have more yield more reactants are needed and if we add some more H2O2 to
it, then we can get the desired graph.
Hence,
A is correct.
Solution:
In
this case, no bonds are broken. But the six X-H bonds and one X-X bond is
formed (as per molecular formula X2H6). So, the sum of all six X-H bond energy and
X-X bond energy should be equal to -2775 KJ/mol, i.e.
Or,
2775=6*395 + (X-X)
(X-X)=405
KJ/mol
(Note:
Not to get confused in sign, the negative sign implies the bond is formed. But,
the bond energy is always positive. And question demands the bond energy value.
So, you must give the answer with positive sign)
The answer is D.
Solution:
Q=msdt/n
=100*4.2*17 / (c*v)
=100*4.2*17 / {2.5 *(50/1000)}
=100*4.2*17 / (2.5 *0.050)
Note: mass is equal to 100 as 50 cm3 of HCl and 50 cm3 ofNaOH are added making total voulume of 100cm3 and we assume 1gm=1cm3.
The unit of volume is in cm3 and we calulate no. of moles in dm3 so the volume is divided by 1000
Solution:
T is the good conductor and in graphite and SiO2, only graphite can conduct electricity. (B and D are incorrect)
MP and BP of S is higer than that of R hence, S is MgO as it has greater charge density than NaCl (ultimately stronger ionic bond and high MP and BP)
So, the answer is C.
Solution:
In ethanol and ice there is presence of hydrogen bond and permanent dipole-dipole bond, not only van der waal. (A and B are incorrect)
In D, the van der waal forces of attraction is not demolished but intensified as liquid is getting converted to solid. (D is incorrect)
Hence, the answer C is correct
Solution:
If you have a double bond then the two carbon atoms on each side cannot rotate (so to speak) and this might lead to cis - trans isomerism if the groups on each side of the bond are suitable.
The ring, depending on its size may or may not come into play depending on whether it hinders any other rotations.
Bond angles depend on a number of factors, not just the ideal angles of isolated atoms. Loan pairs of electrons tend to make other angles smaller and steric hindrance from large groups can also squeeze the rest of the molecule and stop rotations from happening.
The C=C bond in cholesterol as far as I can see has just hydrogen on it, for isomerism you need a lack of symmetry so that the non rotation of the carbon bond makes a difference.
Where rotating the double bond would give you something different and as you can not do this there must be two different molecules. You have no scope for this in your molecule.
And, all the bonds cant apparently lie on a planar, they form a 3D geometry.
The answer is B.