Calculate the molality of 1 litre solution of 93% H2SO4 (weight/volume). The density of the solution is 1.84 g/ml
إجابة
(C)
10.42 m
2
The oxidation number of phosphorus in Ba(H2PO2) is :
إجابة
(C)
+1
3
A mixture of H2C2O4 (oxalic acid) and NaHC2O4 weighing 2.02 g was dissolved in water and solution made upto one litre. Ten millilitres of the solution required 3.0 ml. of 0.1 N sodium hydroxide solution for complete neutralization. In another experiment, 10.0 ml. of the same solution, in hot dilute sulphuric acid medium. require 4.0 ml. of 0.1 N potassium permanganate solution for complete reaction. Calculate the amount of H2C2O4 and NaHC2O4 in the mixture.
إجابة
(C)
H2C2O4 = 1.12 g, NaHC2O4 = 0.90 g
4
A solid mixture (5.0 g) consisting of lead nitrate and sodium nitrate was headed below 600oC until the weight of the residue was constant. If the loss in weight 28.0 percent, find the amount of lead nitrate and sodium nitrate in the mixture.
إجابة
(A)
Pb(NO3)2 = 3.324 g, NaNO3 = 1.676 g
5
According to Bohr's theory, the electronic energy of hydrogen atom in the nth Bohr's orbit is given by $${E_n} = {{ - 21.6 \times {{10}^{ - 19}}} \over {{n^2}}}J$$. Calculate the longest wavelength of light (in Å) that will be needed to remove an electron from the third Bohr orbit of the He+ ion.
إجابة
(A)
2055 Å
6
Amongst the following elements (whose electronic configuration are given below), the one having the highest ionization energy is:
إجابة
(B)
[Ne] 3s23p3
7
The shape of [CH3]+ is _____.
إجابة
(D)
planar
8
The presence of polar bonds in a poly-atomic molecule suggests that the molecule has non-zero dipole moment.
إجابة
(B)
FALSE
9
When zeolite, which is hydrated sodium aluminium silicate is treated with hard water the sodium ions are exchanged with
إجابة
B
D
10
The freezing point of equimolal aqueous solutions will be highest for
إجابة
(D)
C6H12O6 (glucose)
11
The vapour pressure of pure benzene at a certain temperature is 640 mm Hg. A non-volatile non-electrolyte solid weighing 2.175 g is added to 39.0 g of benzene. The vapour pressure of the solution is 600 mm Hg. What is the molecular weight of the solid substance?
