1 P – Block Elements
Match metal ion Column I with colour Column II in the presence of alizarin.
1) A = 1, B = 4, C = 3, D = 2 2) A = 2, B = 1, C = 4, D = 3 3) A = 3, B = 2, C = 1, D = 4 4) A = 2, B = 3, C = 4, D = 1
SOLUTIONS
Alizarin is a red pigment present in madder root, used in dying and gives different colors with different colors i.e. Sr2+→ Pink, Mg2+ → Violet Al3+ → Red, Ba2+ → blue.
2 Chemical Bonding and Molecular Structure
According to MO theory which of the list ranks the oxygen species in terms of increasing bond order $$O_2^{2 - },\,O_2^ + ,O_2^ - \,,\,O_2^{2 - }$$ 1) $$O_2^{2 - },\,O_2^ - ,O_2^ + \,,\,{O_2}$$ 2) $$O_2^ + ,\,{O_2},O_2^ - \,,\,O_2^{2 - }$$ 3) $${O_2},\,{O_2},O_2^ + \,,\,O_2^{2 - }$$ 4) $$O_2^{2 - },\,O_2^ - ,{O_2}\,,\,O_2^ + $$
SOLUTION
According to MOT bond order is given by the formula:
where NA?, NB? are the number of electrons in antibonding and bonding
Bond order of the following is:
$$O_2^{2 - },\,O_2^ - ,{O_2}\,,\,O_2^ + $$
3 Atomic Structure
The ionization energy of the electron in the lowest orbit of hydrogen atom is 13.6 eV. The energies required in eV to remove electron from three lowest orbits of hydrogen atom are 1) 13.6, 6.8, 8.4 2) 13.6, 10.2, 3.4 3) 13.6, 27.2, 40.8 4) 13.6, 3.4, 1.51
Energy of orbitals is gien byformula
E1 = -13.6 eV Z= 1 and n = 1, 2 3 Energy of Inonization=E∞ - En
4 Chemistry in Everyday Life
An example of a psychedelic agent is
1) LSD
2) TNT
3) DNA
4) DDT
5 Electrochemistry
A 0.2M solution of formic acid is 3% ionised. The value of ionization constant is
1) 1.8 2) 1.8 × 10-4 3) 0.018 4) 18
6 S – Block Elements
What is the correct order of increasing solubility of the following salt?
In the give metal bicarbonates, the anion (bicarbonate ion) is same. Hence the solubility will depend on the size of anion. The size of $$Na^+$$ ion is smaller than that of $$K^+$$ ion. Hence sodium bicarbonate has high lattice energy and lower solubility than potassium bicarbonate. Similarly, the size of $$Mg^+$$ ion is smaller than that of $$Ca^+$$ ion. Hence magnesium bicarbonate has high lattice energy and lower solubility than calcium bicarbonate.
7 States of Matter
A mixture of nitrogen and oxygen has a density of 1.00 g L-1 and the average molecular weight of 31.2 g mol-1 at 27°C and 600 mmHg pressure. The mole fraction of nitrogen, assuming ideal gas behaviour, is
1) 0.78 2) 0.60 3) 0.40 4) 0.22
8 D and F Block Elements
Most probable oxidation state of Pb and Sn will be
1) Pb4+ Sn4+ 2) Pb4+ Sn2+ 3) Pb2+,Sn2+ 4) Pb2+,Sn4+
9 Hydrocarbons
Which of the following compounds will not undergo Friedel -Craft's reaction easily?
1) Cumene 2) Xylene 3) Nitrobenzene 4) Toluene
Nitro group being electron withdrawing, deactivates the benzene nucleus to such an extent so that it becomes incapable to give Friedel -Crafts reaction. Nitrobenzene because of its unreactivity towards Friedel-Craft's reaction is used as a solvent for this reaction.
10 Chemical Thermodynamics
?E° of combustion of iso-butylene is -X kJ mol -1 . The value of ?H° is
1) = ?E° 2) > ?E° 3) = 0 4) < ?E°
Your Score:
where NA?, NB? are the number of electrons in antibonding and bonding 