Chemistry - Fill in the Blanks model Questions Chemical Bonding

1. There are ____________________ π (pi) bonds in a nitrogen molecule. (JEE 1982)
Anwer : 2

2. __________ hybrid orbitals of nitrogen are involved in the formation of ammonium ion. (JEE 1982)
Answer sp³

3. The terminal carbon atom in butane is _____________ hybridized. (JEE 1985)
Answer sp³

The shape of [CH3] ⁺ is ------------------------.
(JEE 1990)
Answer: Triangular planar

4.The valence atomic orbitals of carbon in silver acetylide is _________________.
(JEE 1990)

Answer: sp

5.IN P4O10, the number of oxygen atoms bonded to each phosphorus atom is ____________ .
(JEE 1992)

Answer: 4

6.When N2 goes to N2⁺
The N—N bond distance _________ and when O2 goes to )2⁺, the O—O bond distance ______________.

(JEE 1996)
Answer: increases, decreases

Chemistry - Fill in the Blanks Type Questions Chemical Energetics

1. The total energy of one mole of an ideal monatomic gas at 27°C is __________ calories. (JEE 1984)

Answer (3/2)RT = (1.5 mol)[1.987 cal/ (K mol.)](300 K) = 894.15 cal.

2. A system is said to be ___________ , if it can neither exchange matter nor energy with the surroundings. (JEE 1993)

Answer: isolated

3. The heat content of the products is more than that of the reactants in an _____________ reaction. (JEE 1993)

Answer: endothermic

4. When Fe (solid) is dissolved in acqueous hydrochloric acid in a closed vessel, the work done is _________________ . (JEE 1997)

Answer: zero

5. Enthalpy is an ____________ property. (JEE 1997)

Answer: extensive property.

It depends on mass of the substance

Chemistry : Fill in the Blanks Type Questions Chemical Equilibrium

1. The conjugate base of HSO₄^- in acqueous solution is_____________.

(JEE 19820)

Answer: SO₄^2-

2. The hydrolysis of ethyl acetate in ______________________ medium is a _________ order reaction.

(JEE 1986)
Answer : acidic, first order

3. ____________ acid gives _____________ ion.
(options given: hydrobromic acid, hypobromous. Perbromic, bromide, bormite, perbromate)

(JEE 1988)

Answer: Hydrobromic acid, bromide (*Refer TMH Chemistry IIT 2007-Table 7.1)

4. For a given reversible reaction, at a fixed temperature equilibrium constants Kp and Kc are related by ____________________ .
(JEE 1994)

Answer : Kp = Kc (RT) ^{Δ v}g


4a. Solubility of iodine in water is greatly increased by the addition of iodide ions because of the formation of _______________________. (JEE 1994)

Answer: I3^-,

5. A ten fold increase in pressure on the reaction

N2(g) + 3H2(g) ↔ 2NH3(g) at equilibrium results in _____________ in Kp.

(JEE 1996)

Answer: no change

Reason: Kp of an equilibrium reaction is independent of pressure of the system.

6. For a gaseous reaction 2B → A, the equilibrium constant Kp is _____________ to/than Kc.
(JEE 1997)
Answer: smaller

7. In the reaction I^- + I2 → I3^-, the Lewis acid is _______________ .
(JEE 1997)
Answer: I2

Chemistry - Fill in the Blanks Type Questions Electrochemistry

1. The more ___________________ the standard reduction potential, the __________________ is its ability to displace hydrogen from acids.
(JEE 1986)

Answer: negative, greater

2. The electrolysis of molten sodium hydride liberates ______________ gas at the ____________.

(JEE 1989)

Answer H2, anode

3. When an aqueous solution of sodium fluoride is electrolysed, the gas liberated at the anode is _________________ . (JEE 1997 cp)

Answer: O2

Chemistry - Fill in the Blanks model Questions Atomic Structure

1. The mass of a hydrogen atom is ------------------ kg. (JEE 1982)

answer: 1.66*10^-27 kg

2. When there are two electrons in the same orbital, they have ---------------- spins. (JEE 1982)

Answer: opposite or antiparallel

3. Isotopes of an element differ in the number of ______________ in their nuclei. (JEE 1982)

Anwer: neutrons


4. Elements of same mass number but of different atomic numbers are known as ----------.
(JEE 1983)

Answer: isobars


5. Fill in the blanks choosing appropriate words given with brackets)
the uncertainty principle and the concept of wave nature of matter were proposed by ----------------- and -------------------- respectively
(Heisenberg, Schrodinger, Maxwell, de Broglie)
(JEE 1988)

Answer: Heisenberg, de Broglie

Chemistry - Fill in the Blanks model Questions Solid, Liquid, Gas Phases

1. Cp – Cv for an ideal gas is ____________.
(JEE 1984)

Answer : R
(See page No. 67 H C Verma part 2)

2. The rate of diffusion of gas is ______________________ proportional to the square root of molecular mass.
(JEE 1986)

Answer: inversely
(Graham’s law of diffusion: The rate of diffusion of a gas is inversely proportional to the square root of its density or molar mass.)

3. The value of PV for 5.6 litres of an ideal gas is _________________ RT at STP.
(JEE 1987)

Answer: ¼ or 0.25
1 mole of an ideal gas at STP has a volume of 22.4 litres

4. Eight grams of oxygen and hydrogen at 27°C will have the total kinetic energy in the ratio of __________________.
(JEE 1989)

Answer: 1:16

Reason: For a mixture of gases, in thermal equilibrium, average kinetic energy of all molecules is same.

(½)*m1* v1² = (1/2)*(m2*v2²

Oxygen’s molecular weight is 32 and hence 8 grams will have 8/32 = ¼ moles.
Hydrogen’s molecular weight is 2 and hence 8 grams will have 8/2 = 4 mols

Total kinetic energy of oxygen moleculues = (¼ )* (½)*m1* v1²
Total kinetic energy of hydrogen molecules = 4*(1/2)*(m2*v2²

The ratio will be (1/4)/4 = 1/16 as remaining terms or equal in both cases.

5. The shape of [CH3] ⁺ is ___________________.
(JEE 1990)

Answer: Planar

6. Among N₂0, S0₂, I₃3⁺, I₃^-, the linear species are ____________ and __________ .
(JEE 1997).

Answer: N₂0, I₃3^-

7. A liquid which is permanently supercooled is frequently called as ___________.
(JEE 1997)
Answer: glass