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JEE Advance - Chemistry (1984)

1
When alpha particles are sent through a thin metal foil, most of them go straight through the foil because
Answer
A
C
2
The electron energy in hydrogen atom is given by E = (-21.7 $$\times$$ 10-12)/n2 ergs. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength (in cm) of light that can be used to cause this transition?
Answer
(A)
5.42 x 10^-12 ergs, 3.66 x 10^-5 cm
3
On hybridization of one s and one p orbitals we get:
Answer
(B)
two orbitals at 180o
4
The total energy of one mole of an ideal monatomic gas at 27o is _______ calories.
Answer
900
5
Which electronic level would allow the hydrogen atom to absorb a photon but not to emit a photon?
Answer
(D)
1s
6
An isotone of $${}_{32}^{76}Ge$$ is
Answer
B
D
7
When alpha particles are sent through a thin metal foil, most of them go straight through the foil because
Answer
A
C
8
The electron energy in hydrogen atom is given by E = (-21.7 $$\times$$ 10-12)/n2 ergs. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength (in cm) of light that can be used to cause this transition?
Answer
(A)
5.42 \(\times\) 10^-12 ergs, 3.67 \(\times\) 10^-5 cm
9
On hybridization of one s and one p orbitals we get:
Answer
(B)
two orbitals at 180o
10
The total energy of one mole of an ideal monatomic gas at 27o is _______ calories.
Answer
900
11
Cp - Cv for an ideal gas is _______
Answer
(B)
R
12
Equal weights of methane and hydrogen are mixed in an empty container at 25oC. The fraction of the total pressure exerted by hydrogen is
Answer
(B)
8/9
13
The hydration energy of Mg++ is larger than that of:
Answer
(B)
Na+
14
The IUPAC name of the compound having the formula is : IIT-JEE 1984 Chemistry - Basics of Organic Chemistry Question 12 English
Answer
(C)
3, 3-dimethylbut-1-ene
15

When 16.8 g of white solid X were heated, 4.4 g of acid gas A, that turned lime water milky was driven off together with 1.8 g of a gas B which condensed to a colourless liquid.

The solid that remained, Y, dissolved in water to give an alkaline solution, which with excess barium chloride solution gave a white precipitate Z. The precipitate efferversced with acid giving off carbon dioxide. Identify A, B and Y and write down the equation for the thermal decomposition of X.

Answer
(A)
A is CO2, B is H2O, Y is Na2CO3, X is NaHCO3, Decomposition Equation: 2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g)