The element belongs to thorium series. Which of the following will act as the end product of the series?
82Pb208
82Bi209
82Pb206
82Pb207
Consider the following reversible reactions,
N2(g) + 3H2(g) 2NH3(g) (K1) ...(i)
N2 (g) + O2(g) 2NO (g) (K2) ....(ii)
H2 (g) +
The equilibrium constant for the reaction:
2NH3(g) + will be
K1 K2 K3
The number of moles of sodium acetate to be added to 0.1 M acetic acid for the buffer to have a pH = 4.7 is [pKa for acetic acid is 4.7]
0.2
0.4
0.1M
None of these
If radius of first Bohr's orbit of hydrogen atom is 'x', then the de-Broglie wavelength of electron in 3rd orbit is nearly
2πx
6πx
9x
x/3
B.
6πx
Which of the following statements is false?
1. Non-bonding pairs occupy more space than bonding pairs.
2. The bonding orbitals in trigonal bipyramidal molecule are described as sp3d hybrids.
3. SnCl2 has linear shape.
4. PCl and AlCl are isoelectronic.
1
2
3
4
Match List I with List II and select the correct answer using the codes.
List I | List II |
A. Spontaneous process | 1 Δh < 0 |
B. Exothermic process | 2. Heat of reaction |
C. Enthalpy at constant pressure | 3. ΔG < 0 |
D. Cyclic process | 4. ΔU= 0, ΔH = 0 |
A B C D
4 2 1 3
A B C D
3 1 2 4
A B C D
1 3 4 2
A B C D
1 2 3 4
Standard enthalpies of formation of O3, CO2, NH3 and HI are 142.2, -393.2,- 46.2 and 25.9 kJ mol-1 respectively. Decreasing order of their stability is
HI > NH3 > CO2 > O3
NH3 > CO2 > HI > O3
CO2 > NH3 > HI > O3
O3 > HI > NH3 > CO2
A drop of solution (volume 0.05 mL) contains 3 x 10-6 mole H+. If the rate constant of disappearance of H+ is 1.0 x 107 molL-1 s-1, how long would it take for H+ in drop to disappear?
4 × 10-6 s
1× 10-7 s
3× 10-6 s
6 × 10-9 s
First and second ionisation enthalpies of Mg are 737. 76 and 1450.73 J mol-1 respectively. The energy required to convert all the atoms of magnesium to magnesium ions present in 24g of magnesium vapours is
24 kJ
2.188 kJ
12 kJ
4.253 kJ