Chemistry Mcqs & Quiz Class 11 English Medium
1.(chemistry) Important Mcqs)The charge to mass ratio (e/m) of positive particles
(a) varies with the nature of gas in discharge tube
(b) is independent of the gas in discharge tube
(c) is constant
(d) none of the above
Mcqs Chemistry
Chemistry Electronic configuration questions
The number of electrons in the outermost shell of Potassium (at. no. 19) is
(a) 1 (b) 2 (c) 8 (d) 9
Out of the following pairs of elements which has the same number of electrons in the outer most energy
level?
(a) helium and lithium (b) boron and carbon (c) carbon and nitrogen (d) lithium and hydrogen
Oxygen has low first ionization energy than nitrogen due to.
More protons (b) spin pair attraction (c) spin pair repulsion (d) more shielding effect
The Principal quantum number is related to the
(a) orbital angular momentum (b) size and shape of the orbital
(c) orientation of the orbital (d) average size of the orbital
A nodal plane separates the two lobes of a p-orbital. There is _______ likelihood of finding the electron
on this plane.
(a) no (b) every (c) either of these (d) none of these
The orbital with n = 3 and l= 2 is
(a) 3s (b) 3p (c) 3d (d) 3f
The energy associated with electrons in s, p, d and f orbitals of a particular principal quantum number in
hydrogen atom is in the order
(a) s = p = d = f (b) s <p <d <f (c) p <d <f <s (d) f <d <p <s
The sum of all quantum numbers of the last electron in lithium atom is
(a) 3/2 (b) 2 (c) 5/2 (d) 3
The second electron affinity of an element is always (Chemistry)
(a) zero (b) positive (c) negative (d) infinity
The electronic configuration of isotopes of an element is _______.
(a) same (b) similar (c) different (d) none of these
Which isotope of chlorine out of 17Cl35 and 17Cl37 has greater number of neutrons than the protons?
(a) 17Cl35 (b) 17Cl37 (c) neither of the two (d) both
Which of the following is isoelectronic with Cl–1?
(a) S2– (b) P3– (c) K+ (d) All
Electronic configuration of Cu2 + will be.
[Ar] 4s1, 3d9 (b) [Ar] 4s1, 3d10 [Ar] 4s0, 3d9 [Ar] 4s1, 3d8
Factors governing the formation of an ionic bond are
low ionization energy of metal and high electron affinity of non-metal atom
high ionization energy of metal and high electron affinity of non-metal atom
low ionization energy of metal atom and low electron affinity of non-metal atom
high ionization energy of metal and low electron affinity of non-metal atom
The lattice energy is the amount of energy that
is released when one cation combines with one anion
is released when one mole of cations combine with one mole of anions
is released when one mole of an ionic compound is formed from its cations and anions
A pure covalent bond involves
sharing of electrons between a metal and a non-metal atom
sharing of electrons between two metal atoms
sharing of electrons between two atoms having similar electronegativity
sharing of electrons between two atoms having a large difference in electronegativity
The compounds which contain both ionic and covalent bonds are
CHCl3 and CCl4 (b) KCl and AlCl3 (c) KCN and NaOH (d) H2 and CH4
The common feature among the molecules HF, H2O, and NH3 is
intramolecular H-bonding (b) intermolecular H-bonding
that they contain no polar bonds (d) that their dipole moment is zero
The density of water is maximum at
273 K (b) 277 K (c) 281 K (d) 285 K
In which of the following, the central atom is surrounded by four electron pairs
(a) H2O (b) NH3 (c) CH4 (d) All
Which of the following are isostructural
(a) SO2and CO2 (b) SO2and H2O (c) BCl3 and CHCl3 (d) NH3and CH4
The favorable conditions for the formation of H–bonding are
high electronegativity and small size of the atom bonded to H–atom
low electronegativity and large size of the atom bonded to H–atom
high electronegativity and large size of the atom bonded to H–atom
Among BeF2, BF3, NH3 and CCl4, the polar molecule is
(a) BeF2 (b) BF3 (c) NH3 (d) CCl4
In an endothermic reaction
(a) ER >EP (b) ER <EP (c) ER = EP (d) None of these
For exothermic reactions, H is _______ while for endothermic reactions it is _______.
(a) positive, negative (b) positive, positive (c) negative, negative (d) negative, positive
By convention, the standard heat of formation of all elements is assumed to be
(a) zero (b) negative (c) positive (d) infinity
Organic chemistry elements for xi year
Which of the following always has a negative value?
(a) heat of formation (b) heat of reaction (c) heat of combustion (d) heat of solution
Organic Chemistry Class Matric Classes
The heat of neutralization of a strong acid and a strong base is always
(a) zero (b) constant (c) positive (d) changing
The average amount of energy required to break all bonds of a particular type in one mole of the substance
is called
(a) heat of reaction (b) bond energy (c) heat of transition (d) heat of bond formation
31. Hess’s law is used to determine(physical chemistry)
i. heat of formation of substances which are otherwise difficult to measure
ii. heat of transition
iii. heats of various other reactions like dimerization
iv. all of the above
32. If we mix 50cm3 of HCl in 50cm3 of NaOH. Conc. Of both is 1.0 mol/dm3. Temperature changes from 21.3 to 27.8C. enthalpy change of neutralization will be.
a. 2717j 54340j 5430J None
33. At constant temperature, the pressure of the gas is reduced to one third, the volume
i. reduces to one third (b) increases by three times
ii. remains the same (d) cannot be predicted
34. For one mole of a gas the kinetic energy is given by
a. (a) E = 1/2 RT (b) E = 3/2 RT (c) E = 5/2 RT (d) E = 7/2 RT
35. The real gases show nearly ideal behaviour at
i. low pressures and low temperatures (b) high pressures and low temperatures
ii. high pressures and high temperatures (d) low pressures and high temperatures
36. Association of molecules in water is due to
a. (a) surface tension (b) viscosity (c) hydrogen bonding (d) optical activity
37. The rate of evaporation of a liquid depends upon
a. (a) surface area (b) temperature (c) nature of liquid (d) all of these
38. The vapor pressure of non-polar liquids is
i. fairly high as compared to polar liquids (b) fairly low as compared to polar liquids
b. (c) the same as that of polar liquids (d) none of these
39. Which is not true about the solid state?Solid state chemistry
a. (a) they have definite shape and volume (b) they have high density and low compressibility
b. (c) they have high attractive forces among molecules (d) they have high vapour pressure
40. A crystalline solid does not have one of the following properties. It is
a. (a) anisotropy (b) sharp melting points (c) isotropy (d) definite and regular geometry
41. Na+Cl–, Cs+Cl– are the example of
i. cubic crystal system (b) tetragonal crystal system
ii. orthorhombic crystal system (d) rhombohedral crystal system
42. The total number of atoms in a body centered cubic unit cell is
a. (a) 1 (b) 2 (c) 3 (d) 4
43. The co-ordination number of Na+ in Na+Cl– crystal is
a. (a) 2 (b) 4 (c) 6 (d) 8
44. In an ionic crystal, a cation and an anion leave the lattice to cause two vacancies. This defect is called
a. (a) Schottky defect (b) Frenkel defect (c) interstitial defect (d) none of these
45. A chemical system is at equilibrium(Physical Chemistry)
i. when the rate of the forward reaction becomes zero
ii. when the rates of the forward reaction and the reverse reaction are equal
iii. when all of the reactants have been used up
iv. when the rates of the forward reaction and the reverse reaction are both zero
46. Which of the following represent equilibrium constants?
i. weak acid or weak base dissociation constant
ii. Kcfor a reaction
iii. concentration of a strong acid in water
iv. (a) and (b) represent equilibrium constants
47. Which of the following will change the equilibrium constant for a reaction mixture?
i. changing temperature (b) adding an inert gas
ii. increasing pressure by decreasing volume (d) all of these
48. Which of the following can change the value of the equilibrium constant for a reaction
i. changing the concentration of the reactants (b) adding a catalyst
ii. changing the solvent (d) removing the products as they are formed
49. In writing equilibrium constant expressions, which of the following quantities can be used to represent
50. the amount of reactants and products?
a. (a) concentrations (b) partial pressures (c) mole fractions (d) (a) and (b) only
52. Calculate the equilibrium partial pressure of PCl3 in a 3.00 L vessel that was charged with 0.123 atm of
a. PCl5.
b. PCl5(g) -<-------PCl3(g) + Cl2(g) (Keq= 0.0121)
c. (a) 0.123 atm (b) 0.0110 atm (c) 0.0330 atm (d) 0.0900 atm
Numerical Chemistry Class 11
53. A chemist dissolves an excess of BaSO4 in pure water at 25°C. If its Ksp= 1 × 10–10, what is the
a. concentration of the barium in the water?
b. (a) 10–4 M (b) 10–5 M (c) 10–6 M (d) 10–15 M
54. Which of the following includes all the aims of kinetics?
to measure the rate of a reaction
a. (ii) to be able to predict the rate of a reaction
b. (iii) to be able to establish the mechanism by which a reaction occurs
c. (iv) to be able to control a reaction
d. (a) (i), (ii) and (iii) (b) (i) and (ii)
e. (c) (i) and (iii) (d) (i), (ii), (iii) and (iv)
55. Reaction rates can change with
(a) (a) temperature (b) the addition of a catalyst (c) reactant concentrations (d) all of these
very important ppsc chemistry questions
ii. Reaction rates generally
iii. are constant throughout a reaction
iv. are smallest at the beginning and increase with time
v. are greatest at the beginning of a reaction and decrease with time
vi. no such generalisations can be made
vii. For first-order reactions the rate constant, k, has the unit(s)
b. (a) l mol–1 (b) time–1 (c) (mol/l)–1 time–1 (d) time mol l–1
56. The first-order rate constant for the decomposition of N2O5 to NO2 and O2 at 70°C is 6.82 × 10–3 s–1.
Suppose we start with 0.300 mol of N2O5(g) in a 0.500 L container. How many moles of N2O5 will
remain after 1.5 min?
a. (a) 0.081 mol (b) 0.555 mol (c) 0.325 mol (d) 0.162 mol
57. To study the rate of a reaction, it is necessary to
i. identify the reactants
ii. know the relative amounts of reactants used
iii. know the overall chemical equation for the reaction
iv. all of the above are necessary
Why is a minimum energy needed for an effective collision?
- energy is needed to break bonds
- energy is needed to orient the particles correctly
- a minimum energy is needed, so that the particles will collide many times per second
- enough energy is needed to give off heat in a reaction
What happens when molecules collide with less than the activation energy needed for the reaction?
- they stick together but do not react
- they react, but more slowly
- they react if the bonds are arranged in the correct orientation
- they do not react; they simply bounce off of each other
A first order reaction requires 8.96 months for the concentration of reactant to be reduced to 25.0% of its original value.
What is the half life of the reaction?
(a) 4.48 months (b) 2.24 months (c) 8.96 months (d) 17.9 months
Latest Class 11 Mcqs Chemistry
A catalyst will affect the rate of the forward reaction by changing the
(a) activation energy (b) heat of reaction (c) heat of formation (d) potential energy of the products
The optimum temperature is that
- The catalytic activity of the catalyst is minimum
- when catalytic activity of the catalyst is maximum
- catalytic activity of the catalyst is zero
- then the catalytic activity of the catalyst is negative
Quiz Chemistry Class 10 Updated and new
According to Bronsted-Lowry concept, an acid is a substance that
accepts a proton (b) releases a proton(c) accepts an electron pair (d) releases an electron pair
The pOH and pH of 0.1 M aqueous HCl will be
(a) 13, 1 (b) 1, 13 (c) 14, 0 (d) 0, 14
The solution A has pH equal to 2 and solution B has pH of 4. Which one of the following is true? Inorganic Chemistry Questions
- The solution B is 100 times more acidic than solution A
- A solution B is twice more acidic than solution A
- This solution A is twice more acidic than solution B
- solution A is 100 times more acidic than solution B