11Na24 1s radioactive and it decays to:
9F20 and -particles
13Al24 and positron
11Na23 and neutron
12Mg24 and -particles
A 100 mL 0.1 = (M) solution of ammonium acetate is diluted by adding 100 mL of water. The pH of the resulting solution will be (pKa of acetic acid is nearly equal to pKb of NH4OH).
4.9
5.0
7.0
10.0
C.
7.0
Ammonium acetate is a salt of a weak acid and a weak base. When solutions of such salts diluted resulting pH of the solution is calculated from the following relationship,
pH = 7 + 1/2 pKa - 1/2 pKa
PKa = pKb (given)
pH of diluted solution = 7
Equal weights of CH3 and H2 are mixed in an empty container at 25°C. the fraction of the total pressure exerted by H2 is:
1/9
1/2
8/9
16/17
In a reversible chemical reaction at equilibrium, if the concentration of any one of the reactants is doubled, then the equilibrium constant will:
also be doubled
be halved
remains the same
becomes one-fourth
Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle?
x .p h/(4)
x . h/(4)
. h/(4)
. h/(4)
The equivalent weight of K2Cr2O7 in acidic medium is expressed in terms of its molecular weight (M) as:
M/3
M/4
M/6
M/7
Which of the following is correct?
Radius of Ca2+ < Cl- < S2-
Radius of Cl- < S2- < Ca2+
Radius of Cl- = S2- = Ca2+
Radius of S2- < Cl- < Ca2+
The state of hybridization of the central atom and the number of lone pairs over the central atom in POCl3
are:
sp , 0
sp2 , 0
sp3 , 0
dsp2 , 1
20 mL 0.1 (N) acetic acid is mixed with 10 ml 0.l(N) solution of NaOH. The pH of the resulting solution is (pKb of acetic acid is 4.74)
3.74
4.74
5.74
6.74
Which of the following is correct?
Evaporation of water causes an increase in disorder of the system
Melting of ice causes a decrease in the randomness of the system
Condensation of steam causes an increase in disorder of the system
There is practically no change in the randomness of the system when water is evaporated