Free Class 6 to Class 12 Chemistry Solutions and Answers

How many years it would take to spend Avogadro's number of rupees at the rate of \({1}\) million repees in one second?

Correct20

What volume of \({3}\) molar \({H}{N}{O}_{{{3}}}\) is needed to oxidise \({8}{g}\) of \({F}{e}^{{{3}+}}\), \({H}{N}{O}_{{{3}}}\) gets converted to \({N}{O}\) ?
(A) \({8}{m}{L}\)
(B) \({16}{m}{L}\)
(C) \({32}{m}{L}\)
(D) \({64}{m}{L}\)

Chemistry|Class 11

Correct33

One mole of \({N}_{{{2}}}{H}_{{{4}}}\) loses ten moles of electrons to form a new compound \({A}\). Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in \({A}\)? (There is no change in the oxidation state of hydrogen.)

Chemistry|Class 11

Correct20

The number of d-electrons in \({F}{e}^{{{2}+}}{\left({Z}={26}\right)}\) is not equal to that of :
(A) p-electrons in \({N}{e}{\left({Z}={10}\right)}\)
(B) p-electrons in \({M}{e}{\left({Z}={12}\right)}\)
(C) p-electrons in \({F}{e}{\left({Z}={26}\right)}\)
(D) p-electrons in \({C}{l}{\left({Z}={17}\right)}\)

Chemistry|Class 11

Correct9

Which one is reversible process?
(A) Melting of ice at \({10}^{{\circ}}{C}\)
(B) Mixing of two gases
(C) Evaporation of water at \({100}^{{\circ}}{C}\) and \({1}{a}{t}{m}\) pressure
(D) none of these

Chemistry|Class 11

Correct18

Is it possible for a weak acid, say acetic acid \({\left({K}_{{{a}}}={1.8}\times{10}^{{-{5}}}\right)}\) to have a pH = 7 by adding any other chemical and if so how much amount of it should be added ?

Chemistry|Class 11

Correct42

\({H}_{{{2}}}{S}\) is passed through \({\left({C}{H}_{{{3}}}{C}{O}{O}\right)}_{{{2}}}\) Zn and \({Z}{n}{C}{I}_{{{2}}}\) solutions separately. White ppt. will be noticed in :
(A) \({\left({C}{H}_{{{3}}}{C}{O}{O}\right)}_{{{2}}}{Z}{n}\) solution
(B) \({Z}{n}{C}{I}_{{{2}}}\) solution
(C) both (a) and (b)
(D) none of these

Chemistry|Class 11

Correct50

When temperature is lowered \({N}{O}_{{2}}\) dimerises . It is accompanised by :
(A) an increase in pressure
(B) darkening in colour
(C) decrease in paramangetism
(D) increase in paramagetism

Chemistry|Class 11

Correct14

Structrue of \({I}{C}{{O}_{{2}}^{{-{}}}}\) is :
(A) trigonal
(B) distorted trigonal bipyramid
(C) octahedral
(D) square planar

Chemistry|Class 11

Correct2

\({N}_{{2}}\) and \({O}_{{2}}\) are converted to mono cations \({{N}_{{2}}^{+}}\) and \({{O}_{{2}}^{+}}\) respectively, which statement is wrong ?
(A) in \({{N}_{{2}}^{+}}\) , the \({N}-{N}\) bond weakens
(B) In \({O}-{2}^{+}\) , the \({O}-{O}\) bond order increase
(C) in \({{O}_{{2}}^{+}}\) , the paramagnetism decrease
(D) \({{N}_{{2}}^{+}}\) become diamagnetic

Chemistry|Class 11

Correct45

Statement : MO configuration of \({C}{O}\) is :
\(\sigma{1}{s}^{{2}},\sigma^{\ast}{1}{s}^{{2}},\sigma{2}{s}^{{2}},\sigma{2}{{p}_{{x}}^{{2}}},\pi{2}{{p}_{{y}}^{{2}}},\pi{2}{{p}_{{z}}^{{2}}},\sigma^{\ast}{2}{s}^{{2}}\)
Explanation : the energy level \(\sigma^{\ast}{2}{s}^{{2}}\) possesses higher energy because then only higher bond length in \({C}{O}\) that \({C}{O}^{+}\) can be explained .
(A) \({S}\) is correct by \({E}\) is wrong .
(B) \({S}\) is wrong but \({E}\) is wrong .
(C) Both \({S}\) and \({E}\) are correct and \({E}\) is correct explanation os \({S}\) .
(D) Both \({S}\) and \({E}\) are conrrect and \({E}\) is correct explanation os \({S}\).

Chemistry|Class 11

Correct12

The bond between two identical non-metal atoms has a pair of electrons:
(A) unequally shared between the two
(B) transferred fully from one atom to another
(C) with identical spins
(D) equally shared between them

Chemistry|Class 12

Correct6

Kinetic energy of a molecule is zero at \({0}^{{\circ}}{C}\)___

Chemistry|Class 12

Correct35

One of the consituents of German silver is
(A) Ag
(B) Cu
(C) Mg
(D) Al

Chemistry|Class 12

Correct24

The equilibrium \({S}{O}_{{{2}}}{C}{l}_{{{2}}}{\left({g}\right)}\Leftrightarrow{S}{O}_{{{2}}}{\left({g}\right)}+{C}{l}_{{{2}}}{\left({g}\right)}\) is attained at \({25}^{{\circ}}{C}\) in a closed container and an inert gas, helium is introduced. Which of the following statements are correct?
(A) Concentration of \({S}{O}_{{{2}}},{C}{l}_{{{2}}}\) and \({S}{O}_{{{2}}}{C}{l}_{{{2}}}\) change
(B) More chlorine is formed
(C) Concentration of \({S}{O}_{{{2}}}\) is reduced
(D) None of the above

Chemistry|Class 12

Correct5

Silver jewellery items tarnish slowly in air due to their reaction with ____.

Chemistry|Class 12

Correct26

Statement I: Alkali metals dissolve in liquid ammonia to give blue solutions.
Statement II: Alkali metals in liquid ammonia give solvated species of the type \({\left[{M}{\left({N}{H}_{{{3}}}\right)}_{{{n}}}\right]}^{{\oplus}}\) (M = alkali metals).
(A) Statement I is correct , Statement II is correct , Statement II is the correct explanation of Statement I
(B) Statement I is correct , Statement II is correct , Statement II is not the correct explanation of Statement I
(C) Statement I is correct , Statement II is incorrect
(D) Statement I is incorrect , Statement II is correct

Chemistry|Class 12

Correct33

Conisder the chemical reaction
\({N}_{{{2}}}{\left({g}\right)}+{3}{H}_{{{2}}}{\left({g}\right)}\rightarrow{2}{N}{H}_{{{3}}}{\left({g}\right)}\)
The rate of this reaction can be expressed in terms of time derivatives of the concentration of \({N}_{{{2}}}{\left({g}\right)},{H}_{{{2}}}{\left({g}\right)}\), or \({N}{H}_{{{3}}}{\left({g}\right)}\). Identify the correct relationship among the rate expresisons.
(A) \({R}{a}{t}{e}=-\frac{{{d}{\left[{N}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=-\frac{{1}}{{3}}\frac{{{d}{\left[{H}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=\frac{{1}}{{2}}\frac{{{d}{\left[{N}{H}_{{{3}}}\right]}}}{{\left.{d}{t}\right.}}\)
(B) \({R}{a}{t}{e}=-\frac{{{d}{\left[{N}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=-{3}\frac{{{d}{\left[{H}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}={2}\frac{{{d}{\left[{N}{H}_{{{3}}}\right]}}}{{\left.{d}{t}\right.}}\)
(C) \({R}{a}{t}{e}=-\frac{{{d}{\left[{N}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=\frac{{1}}{{3}}\frac{{{d}{\left[{H}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=\frac{{1}}{{2}}\frac{{{d}{\left[{N}{H}_{{{3}}}\right]}}}{{\left.{d}{t}\right.}}\)
(D) \({R}{a}{t}{e}=-\frac{{{d}{\left[{N}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=-\frac{{{d}{\left[{H}_{{{2}}}\right]}}}{{\left.{d}{t}\right.}}=\frac{{{d}{\left[{N}{H}_{{{3}}}\right]}}}{{\left.{d}{t}\right.}}\)

Chemistry|Class 12

Correct8

An aqueous solution is 1.00 molalin KI. Which change will cause the vapour pressure of the solution to increase ?
(A) addition of water
(B) addtion of NaCl
(C) addtion of \({N}{a}_{{{2}}}{S}{o}_{{{4}}}\)
(D) Addition of 1.0 molal KI

Chemistry|Class 11

Correct44

What is meant by the term "coordination number"?
b. What is the coordination number of atoms:
i. in a cubic-packed structure?
ii. In a body-centreds structure?

Chemistry|Class 12

Correct14

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