The energy of the electron in the second and the third Bohr's orbits of the hydrogen atom is -5.42 $$\times$$ 10-12 erg and -2.41 $$\times$$ 10-12 erg respectively. Calculate the wavelength (in Å) of the emitted radiation when the electron drops from the third to second orbit.
إجابة
(C)
6603 Å
2
If 0.50 mol of BaCl2 is mixed with 0.20 mol of Na3PO4, the maximum amount of Ba3(PO4)2 that can be formed is
إجابة
(D)
0.10
3
1 mole of N2H4 loses 10 moles of electrons to form a new compound Y. assuming that all nitrogen appears in the new compound , what is the oxidation state of nitrogen in Y ? (there is no change in the oxidation state of hydrogen)
إجابة
(C)
+3
4
A 1.00 gm sample of H2O2 solution containing X percent H2O2 by weight requires X ml of a KMnO4 solution for complete oxidation under acidic conditions. Calculate the normality of the KMnO4 solution.
إجابة
(C)
0.588 N
5
Balance the following Equations:
(i) Cu2O + H+ + $$NO_3^ - \to $$ Cu2+ + NO + H2O
(ii) K4[Fe(CN)6] + H2SO4 + H2O $$\to$$ K2SO4 + FeSO4 + (NH4)2SO4 + CO
Rutherford's experiment on scattering of $$\alpha-particles$$ showed for the first time that the atom has
إجابة
(C)
nucleus
7
The correct order of second ionisation potential of carbon, nitrogen, oxygen and fluorine is
إجابة
(C)
O > F > N > C
8
The angle between two convalent bonds is maximum in ________. (CH4, H2O, CO2)
إجابة
(C)
CO2
9
If a molecule MX3 has zero dipole moment, the sigma bonding orbitals used by M (atomic number < 21) are
إجابة
(C)
sp2 hybrid
10
Equal weights of methane and oxygen are mixed in an empty container at 25oC. The fraction of the total pressure exerted by oxygen is
إجابة
(A)
1/3
11
The temperature at which a real gas obeys the ideal gas aws over a wide range of pressure is
إجابة
(B)
Boyle temperature
12
The ratio of root mean square velocity to average velocity of a gas molecule at a particular temperature is
إجابة
(A)
1.086:1
13
A solution of sodium metal in liquid ammonia is strongly reducing due to the presence of
إجابة
(D)
solvated electrons
14
Give reasons of the following:
Sodium carbonate is made by Solvay process but the same process is not extended to the manufacture of potassium carbonate.
إجابة
(A)
Potassium bicarbonate is more soluble than sodium bicarbonate, making it difficult to precipitate.
15
The vapour pressure of pure benzene is 639.7 mm of mercury and the vapour of a solution of a solute in benzene at the same temperature is 631.9 mm of mercury. Calculate this molality of the solution.
