For \(SN_2\) reaction, the increasing order of the reactivity of the following alkyl halides is:
(A) \(CH _3 CH _2 CH _2 CH _2 Br\)
(B) \(CH 3 CH 2 CH ( Br ) CH 3\)
(C) \(( CH 3) 3 CBr\)
(D) \(( CH 3) 2 CHCH 2 Br\)

p-block elements are placed in groups 13 to 18 of the periodic table. Group 15 is nitrogen family. Nitrogen makes various compounds like \(NH _3, HNO _3, N_2 O , NO _2\) etc. Phosphorus exists in the form of white and red phosphorus. White phosphorus glows in dark. \(PH _3\) gas is used as smoke screen. Group 16 is called oxygen family. Dry air contains \(21\% O _2\) gas by volume. Combined sulphur exists as sulphates such as gypsum, epsome salt, baryte etc. The allotropic forms of sulphur are Rhombic and monoclinic sulphur. \(S_2\) is paramagnetic like \(O_2\) and it stable at high temperature.
Group 17 is Halogen family. \(F_2\) is highly reactive, \(C l_2\) is greenish yellow gas. Both \(S O_2\) and \(C l_2\) are used for bleaching. Group 18 is Noble gas family but some noble gases also form compounds.
Complete hydrolysis of \(XeF _6\) gives HF and \(XeO _3\) as main products.
Sulphate of magnesium of the following is :

Read the passage carefully and answer the following questions
Aldehydes, carboxylic acids and ketones are widespread in the animal and plant kingdoms. They play a pivotal role in various biochemical processes of life. Their presence in nature adds fragrance and flavor. These compounds are widely used in food products, pharmaceuticals, paints, resins and other important product industries. These compounds are prepared by various laboratory methods, which mainly include oxidation, formylation, acylation and reduction. Due to the polar nature of the carbonyl group in aldehydes and ketones, they can exhibit different reactions like nucleophilic addition. They do exhibit redox and various condensation reactions which lead to the formation of various important compounds. On the other hand, the carboxylic acids are mainly prepared by oxidation and hydrolysis of different compounds. The carboxylic acid consists of a carbonyl group and the hydroxy group (attached to the carbonyl carbon atom). This makes it possible for the carboxylic acid to participate in various chemical reactions which involve cleavage of the C-OH bond and the O-H bond along with the reactions involving the complete - COOH group.
Arrange the following in the increasing order of their \(p K_{ a }\) values :
(A) \(CF _3- COOH\)
(B) \(O _2 N- CH _2- COOH\)
(C) \(NC - CH _2- COOH\)
(D) \(H - COOH\)
Choose the correct answer from the options given below :

Which is not the limitation of valence bond theory involving coordination compound.

The C-O-H bond angle in alcohols is slightly less than tetrahedral angle \(109^{\circ} 28^{\prime}\) due to:

Which among the following shows positive deviation from Raoult's law?

Ascorbic Acid is

If a person \(A\) speaks the truth in \(80 \%\) cases and the person \(B\) speaks the truth in \(75 \%\) cases, then the probability that they contradict each other in a statement is:

Points of discontinuity of the greatest integer function \(f(x)=\lfloor x\rfloor\), where \(\lfloor x\rfloor\) denotes integer less than or equal to \(x\), are

Which one of the following structure is haploid (n) in relation to male reproductive system?

From the following, choose the element for impurity atoms with which pure silicon should be doped to make it a p-type semiconductor:

Match List-l with List-ll

List-I	List-II
(A) The measurable characteristic of a population is called	(I) sample
(B) The measurable characteristics of a sample is called	(II) Alternative hypothesis
(C) A smaller group of a population selected to represent a population is caller	(III) Parameter
(D) The assumption made opposite to the null hypothesis is called	(IV) statistic

Choose the correct answer from the options given below:

A point charge is kept at the centre of a metallic insulated spherical shell. Then :