Answer the question on the basis of passage given below:
In the periodic table, the d-block contains the elements of group \(3\) to \(12\). The d-orbitals are progressively filled in each of the four long periods. The elements of d block referred as transition metals have partly filled d orbitals and exhibit certain characteristic properties such as variety of oxidation states, formation of coloured ions, act as catalyst and show paramagnetic behaviour.
The two inner transition metals series \(4f\) and \(5f\) are known as Lanthanoids and Actinoids respectively. The lanthanoids resemble one another more closely as compared to ordinary transition elements in any series.
For the four successive transition elements given below, the stability of +2 oxidation state will be:
A. \(\operatorname{Cr}( Z =24)\)
B. \(Mn ( Z =25)\)
C. \(Fe ( Z =26)\)
D. \(Co ( Z =27)\)
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Read the passage carefully and answer the questions
Sodium dichromate \(Na _2 Cr _2 O _7\) and Potassium dichromate \(K _2 Cr _2 O _7\) are strong oxidizing agents; in acidic solution, its oxidising action can be represented as follows :
\(Cr _2 O _7^{2-}+14 H ^{+}+6 e^{-} \rightarrow 2 Cr ^{3+}+7 H _2 O \left( E ^{\circ}=1.33 V\right)\)
The chromates and dichromates are interconvertible in aqueous solution depending upon pH of the solution.
The chromate ion is tetrahedral whereas the dichromate ion consists of two tetrahedra sharing one corner with \(Cr - O - Cr\) bond angle of \(126^{\circ}\)
Potassium permanganate is prepared by fusion of \(MnO _2\) with an alkali metal hydroxide and an oxidising agent like \(KNO _3\).
This produces the dark green \(K _2 MnO _4\) which disproportionates in a neutral or acidic solution to give permanganate. It is a strong oxidizing agent. Hydrogen ion concentration of the solution plays
an important part in the reduction of permanganate to manganate, manganese dioxide and manganese(II) salt.
Potassium permanganate forms dark purple (almost black) crystals which are isostructural with those of \(KClO _4\).
The salt is not very soluble in water \((6.4 g / 100 g\) of water at 293 K ), but when heated it decomposes at 513 K .
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Which of the following is correct about the nature of ligand?

A solution of 2.5 g of ethanoic acid in 75 g of benzene is prepared. What is the molar mass of ethanoic acid, moles of ethanoic acid, mass of benzene and molality of ethanoic acid?
(A) \(0.556 \text{ mol } kg^{-1}\)
(B) \(0.0417 \text{ mol}\)
(C) \(60 \text{ g } mol^{-1}\)
(D) \(0.075 \text{ kg}\)
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Answer the question on the basis of passage given below :
Strong oxidising agents oxidise toluene and its derivatives to benzoic acid. However, it is possible to stop the oxidation at the aldehyde stage with suitable reagents that convert the methyl group to an intermediate that is difficult to oxidise further.
Conversions that can be done by same reagent are:
(A) Benzaldehyde to 2-nitrobenzaldehyde
(B) Propan-1-ol to propanal
(C) Pent-3-en-2-ol to pent-3en-2-one
(D) Butanal to Butan-1-ol
(E) Methanal to Ethanol
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Mercury is the only liquid metal at room temperature due to:

Arrange the following in increasing order of their basic strength in aqueous phase :
(A) \(CH_{3}NH_{2}\)
(B) \(C_{6}H_{5}CH_{2}NH_{2}\)
(C) \(C_{6}H_{5}NH_{2}\)
(D) \((CH_{3})_{3}N\)
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The magnetic flux through a coil perpendicular to the plane is varying according to the relation \( \phi = (7t^3 + 3t^2 - 2t - 2) \, \text{Wb} \). If the resistance of the coil is \( 10\Omega \), the induced current through the coil at t = 2 s, will be

Let \(X\) denote the number of hours a student studies on a selected day. The probability distribution of \(X\) is given by (where \(k\) is some unknown constant)
\(P\left(X=x_i\right)=\left\{\begin{array}{ll}0.5, & \text { if } x_i=0 \\k x_i, & \text { if } x_i=1 \\k\left(4-x_i\right), & \text { if } x_i=2 \text { or } 3 \\0, & \text { otherwise }\end{array}\right.\)
Then the value of \(k\) is

Choose the correct statements :
(A) A nuclide is represented as \( ^A_Z X \)
(B) Nuclids with same number of protons are called isotopes
(C) \( \alpha \)-ray scattering experiments allow determination of the nuclear radius
(D) Nuclids with same number of neutrons are called isotones
(E) The nuclear force distinguishes between neutron and proton
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If A and B are two events such that \(P(B) = \frac{3}{5}\), \(P(A|B) = \frac{1}{2}\) and \(P(A \cup B) = \frac{4}{5}\), then P(A) is equal to:

'Barnacles' growing on the back of whale is a classical example of :

The negatively charged sol among the following is: