In \(\left[ Ni ( en )_3\right] Cl _2\), the geometry of Ni is:

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There are mainly four series of the transition metals, \(3 d\) series ( \(S c\) to Zn), \(4 d\) series (Y to Cd), 5d series (La and Hf to Hg) and 6d series which has \(A c\) and elements from Rf to Cn. The two series of the inner transition metals; \(4 f\) (Ce to Lu) and \(5 f\) (Th to Lr) are known as lanthanoids and actinoids respectively. Their chemical properties are transitional between those of \(s\) and p-block elements. The transition metals (with the exception of Zn, Cd and Hg) are very hard and have low volatility. Their melting and boiling points are high. Transition metals have incomplete d subshell either in neutral atom or in their ions. With partly filled d orbitals these elements exhibit certain characteristic properties such as display of a variety of oxidation states, formation of coloured ions and entering into complex formation with a variety of ligands. The transition metals and their compounds are known for their catalytic activity.
In series Sc to Zn, the lowest enthalpy of atomization is shown by

Answer the question on the basis of passage given below :
Nitrogen differs from rest of the members of group 15 due to its small size, high electronegativity, high ionization enthalpy and non-availability of d orbitals. Nitrogen has unique ability to form pa - pa multiple bonds with itself and with other elements having small size and high electronegativity. Heavier elements of this group do not form pa - pr bonds as their atomic orbitals are so large and diffuse that they cannot have effective overlapping.
Planar structures with \(N - N\) single bond are shown by
A. \(N _2 O _3\)
B. \(N _2 O _4\)
C. \(N _2 O _5\)
D. \(N _2 O\)
E. \(NO\)
Choose the correct answer from the options given below:

Aniline reacts as shown below:
\(C_6 H_5 NH_2 \xrightarrow[0-5^{\circ} C]{NaNO_2+HCl} A \xrightarrow[KCN]{CuCN} B\)
The compound \(B\) is:

The hormone which control the processes of burning of fats, proteins and carbohydrates, with liberation of energy in the body is :

The main cause of basicity of oxoacids of phosphorous is :

What is the Werner secondary valence in complex \([CoCl(NH_3)_5]^{2+}2Cl^-\) ?

The enzyme that can recognise the following palindromic sequence
'5-GAATTC-3'
3'-CTTAAG-5' is _________ :

When a ray of light is incident at an angle of incidence \( 60^\circ \) on one face of an equilateral prism the angle of deviation is found to be minimum. The refractive index of the prism is :

The relation \(R\) on the set \(A=\{1,2,3,4,5\}\), given by \(R(a, b):|a-b|\) is even, is:

In a village, there are three mohallas A, B and C. 60\% farmers in mohalla A believe in new technology of agriculture, while in B it is 70\% and in C is 80\%.
The total probability that a farmer believes in new technology of agriculture is:

Which one of the following compounds is achiral?

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Amines are classified as primary \(\left(1^{\circ}\right)\), secondary \(\left(2^{\circ}\right)\) and tertiary \(\left(3^{\circ}\right)\) depending upon the number of hydrogen atoms replaced by alkyl or aryl groups in ammonia molecules. Aliphatic amines are a stronger bases due to \(+I\) effect of an alkyl groups. Intermolecular hydrogen bonding in primary and secondary amines affects the boiling points of amines. The intermolecular association is more in primary amines than in secondary amines as there are more number of hydrogen atoms available for hydrogen bond formation. Nitro compounds are reduced to amines by passing hydrogen gas in the presence of finely divided nickel, palladium or platinum and also by reduction with metals in an acidic medium. Gabriel synthesis is used for the preparation of primary amines. Primary amines react with nitrous acid to give unstable diazonium-salts which can be used to synthesize a variety of compounds.
The reaction is an example of