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Formaldehyde is the first member of the aldehydic series. It is present in green leaves of plants where its presence is supposed to be due to the reaction of \(CO_2\) with water in the presence of sunlight and chlorophyll. Commercially, formaldehyde is obtained by the controlled oxidation of methane in the presence of molybdenum oxide (\(MoO\)) acting as a catalyst. Formaldehyde is a constituent of a number of polymers also called resins. These are non volatile solids or semi solids which are obtained directly from certain plants and can be synthesized in the laboratory.
Question: How is formalin useful?

When a ferromagnetic substance is placed in a magnetic field, it becomes a permanent magnet because:

A 0.5 M aqueous \(\mathrm{H}_2 \mathrm{SO}_4\) solution is diluted from 2 litres to 20 litres. The concentration of the resulting solution will be

Match List - I with List - II.

List - I	List - II
(A) Antifreeze used in car engine	(I) Phenol
(B) Starting material for picric acid	(II) Glycerol
(C) Wood spirit	(III) Ethylene glycol
(D) By product of soap industry used in cosmetics	(IV) Methanol

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Question based on the following passage:
P-Block elements are placed in group 13 to 18 in the periodic table. Group 15 is nitrogen family.
Nitrogen can react with hydrogen, oxygen, halogens etc. It shows multiple oxidation states in its various oxides i.e. \(N_2O, N_2O_3, N_2O_5\) etc. Important allotropic forms of phosphorus are white, red and black phosporus. Various compounds of phosphorus are phosphine, \(PCl_3, PCl_5\) and oxoacids of phosphorus. Oxidation states \(+1\) to \(+5\) are seen in various oxoacids of phosphorus. Group 17 elements are collectively known as halogens. Bond dissociation enthalpy of \(F_2\) is smaller than \(Cl_2\).
The gases present in group 18 are chemically unreactive, they form only few compounds. Neil Bartlett (in 1962) observed the reaction of a noble gas. Since then, many noble gas compounds have been synthesised.
Amongst all noble gases, only Xe can form large number of compounds because :
(A) Its size is similar to that of Pt
(B) Its \(IE_1\) is almost identical with that of \(O_2\)
(C) Xe is not inert
(D) Xe is very large in size
(E) It has great affinity with \(PtF _6^{-}\)
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Arrange the following solutions according to their increasing boiling points.
A. \(0.1 M Glucose\)
B. \(0.1 M NaCl\)
C. \(0.1 M K _4\left[ Fe ( CN )_6\right]\)
D. \(0.1 M MgCl _2\)
E. \(0.1 M AlCl _3\)
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Substitution nucleophilic unimolecular (S\(_N\)1) reaction is a two step process carried out in polar protic solvents.
It follows kinetics of :
\((CH_3)_3C-Br + OH^– \rightarrow (CH_3)_3COH + Br^–\)

A coil has an inductance of \( L = 0.02 \text{ H} \) and the current is increasing at the rate of \( \frac{dI}{dt} = 200 \text{ A/s} \). The emf induced in it, \( \epsilon \), is:

The correct sequence of steps to obtain gene of interest from pool of DNA is:
(A) Cutting of DNA using restriction endonuclease.
(B) Viewing the ethidium bromide stained gel under UV light.
(C) Loading of DNA in wells.
(D) Cutting and extraction of DNA piece from gel.
(E) Separation of DNA fragments according to their molecular size.
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2-Methyl propene can be prepared by the reaction of:

A charity organization has a fund of Rs. 2, 00, 000 to provide annual grants to students. The grant amount each year is Rs. 15, 000. The fund earns an interest rate of r% per annum. If the interest earned is used entirely to provide the grants, then the annual interest rate r is:

For transmitting a modulated signal of wave length \( \lambda \), the antenna should have minimum size:

Which of the following bond in DNA strand is broken by the action of restriction enzyme?