JEE Advance - Chemistry (1982)

1
The energy released when an electron is added to a neutral gaseous atom is called ______ of the atom.
คำตอบ
(C)
Electron affinity
2
The oxidation number of carbon in CH₂O is
คำตอบ
(C)
0
3
Hydroxylamine reduces iron (III) according to the equation:

2NH₂OH + 4Fe³⁺ $$\to$$ N₂O(g) $$ \uparrow $$ + H₂O + 4Fe²⁺ + 4H⁺

Iron (II) thus produced is estimated by titration with a standard permanganate solution. The reaction is :

$$MnO_4^-$$ + 5Fe²⁺ + 8H⁺ $$\to$$ Mn²⁺ + 5Fe³⁺ + 4H₂O

A 10 ml sample of hydroxylamine solution was Diluted to 1 litre. 50 ml of this diluted solution was boiled with an excess of iron (III) solution. The resulting solution required 12 ml of 0.02 M KMnO₄ solution for complete oxidation of iron (II). Calculate the weight of hydroxylamine in one litre of the original solution. (H = 1, N = 14, O = 16, K =39, Mn = 55, Fe = 56)
คำตอบ
(D)
39.6 g/l
4
The mass of a hydrogen atom is ______ kg.
คำตอบ
(B)
1.673 × 10^-27
5
Isotopes of an element differ in the number of ______ in their nuclei.
คำตอบ
(C)
neutrons
6
When there are two electrons in the same orbital, they have _____ spins.
คำตอบ
(B)
antiparallel
7
The outer electronic configuration of the ground state chromium atom is 3d⁴ 4s²
คำตอบ
(B)
FALSE
8
Calculate the wavelength in Angstrom of the photon that is emitted when an electron in the Bohr orbit, n = 2 returns to the orbit, n = 1 in the hydrogen atom. The ionization potential of the ground state hydrogen atom is 2.17 $$\times$$ 10^-11 erg per atom.
คำตอบ
(C)
1216 Å
9
The element with the highest first ionization potential is
คำตอบ
(C)
nitrogen
10
There are ______ $$\pi$$ bonds in a nitrogen molecule.
คำตอบ
2
11
____ hybrid orbitals of nitrogen atom are involved in the formation of ammonium ion.
คำตอบ
(C)
sp³
12
The ion that is isoelectronic with CO is
คำตอบ
(A)
CN^-
13
Among the following, the molecule that is linear is
คำตอบ
(A)
CO₂
14
The compound with no dipole moment is
คำตอบ
(B)
carbon tetrachloride
15
Helium atom is two times heavier than a hydrogen molecule. At 298 K, the average kinetic energy of a helium atom is
คำตอบ
(C)
same as that of a hydrogen molecule
16
At room temparature, ammonia gas at 1 atm pressure and hydrogen chloride gas at P atm pressure are allowed to effuse through identical pin holes from opposite ends of a glass tube of one metre length and of uniform cross-section. Ammonium chloride is first formed at a distance of 60 cm from the end through which HCL gas is sent in. What is the value of P?
คำตอบ
(C)
4.83 atm
17
MgCl₂.6H₂O on heating give anhydrous MgCl₂
คำตอบ
(B)
FALSE
18
How will you prepare bleaching powder from slaked lime.
คำตอบ
(A)
By treating slaked lime with chlorine gas.
19
Write down the balanced equations for the reaction when:
An alkaline solution of potassium ferricyanide is reacted with hydrogen peroxide.
คำตอบ
(A)
2K3[Fe(CN)6] + H2O2 + 2KOH -> 2K4[Fe(CN)6] + 2H2O + O2