An electronic transition in hydrogen atom results in the formation of Hα line of hydrogen in Lyman series, the energies associated with the electron in each of the orbits involved in the transition (in kcal mol-1) are
-313,6, - 34.84
-313.6, - 78.4
-78.4,- 34.84
-78.4,-19.6
The velocities of two particles A and B are 0.05 and 0.02 ms-1 respectively. The mass of B is five times the mass of A. The ratio of their de-Broglie's wavelength is
2 : 1
1 : 4
1 : 1
4 : 1
The atomic numbers of elements A, B, C and D are Z - 1; Z; Z + 1 and Z + 2, respectively. If 'B' is a noble gas, choose the correct answers from the following statements-
1) 'A' has higher electron affinity.
(2) 'C' exists in +2 oxidation state.
(3) 'D' is an alkaline earth metal.
(1) and (2)
(2) and (3)
(1) and (3)
(1), (2) and (3)
C.
(1) and (3)
Given,
Atomic number of element B = Z ( Noble gas; Belongs to zero group)
Atomic number of element A = Z - 1 (i.e. halogens)
Atomic number of element C = Z + 1 (i.e. Group IA)
Atomic number of element D = Z + 2 (i.e. Group IIA)
Since, element B is a noble gas.
Element A must be a halogen i.e. have highest electron affinity and
Element C must be an alkali metal and exists in +1 oxidation state and
Element D must be an alkaline earth metal with +2 oxidation state.
The bond length of HCl molecule is 1.275 Å and its dipole moment is 1.03 D. The ionic character of the molecule (in percent) (charge of the electron = 4.8 × 10-10 esu) is
100
67.3
33.66
16.83
Which one of the following is a correct set ?
H2O, sp3, angular
BCl3, sp3, angular
NH, dsp2, square planar
CH4, dsp2, tetrahedral
Match the following:
List - I | List - II |
A. 10 gm CaCO3 | (i) 0.224 L CO2 |
B. 1.06 g Na2CO3 | (ii) 4.48 L CO2 |
C. 2.4 g C | (iii) 0.448 L CO2 |
D. 0.56 g CO |
(iv) 2.24 L CO2 (v) 22. 4 L CO2 |
The correct match is
A - iv; B - i; C - ii; D - iii
A - v; B - i; C - ii; D - iii
A - iv; B - i; C - iii; D - ii
A - i; B - iv; C - ii; D - iii
When 25 g of a non-volatile solute is dissolved in 100 g of water, the vapour pressure is lowered by 2.25 × 10-1 mm. If the vapour pressure of water at 20°C is 17.5 mm, what is the molecular weight of the solute ?
206
302
350
276
50 mL of H2O is added to 50 mL of 1 × 10-3 M barium hydroxide solution. What is the pH of the resulting solution ?
3.0
3.3
11.0
11.7
For a crystal, the angle of diffraction (2 θ) is 90° and the second order line has a d value of 2.28 Å. The wavelength (in Å) of X-rays used for Bragg's diffraction is
1.612
2.00
2.28
4.00
In a 500 mL flask, the degree of dissociation of PCl5 at equilibrium is 40% and the initial amount is 5 moles. The value of equilibrium constant in mol L-1 for the decomposition of PCl5 is
2.33
2.66
5.32
4.66