The conversion of hydroxyapatite occurs due to presence of F$$-$$ ions in water. The correct formula of hydroxyapatite is :

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Photochemical smog causes cracking of rubber. Reason (R) : Presence of ozone, nitric oxide, acrolein, formaldehyde and peroxyacetyl nitrate in photochemical smog makes it oxidizing. Choose the most appropriate answer from the options given below :

The gas 'A' is having very low reactivity reaches to stratosphere. It is non-toxic and non-flammable but dissociated by UV-radiations in stratosphere. The intermediates formed initially from the gas 'A' are :

In stratosphere most of the ozone formation is assisted by :

Which one of the following is used to remove most of plutonium from spent nuclear fuel?

BOD values (in ppm) for clean water (A) and polluted water (B) are expected respectively :

The deposition of X and Y on ground surfaces is referred as wet and dry depositions, respectively. X and Y are :

Water sample is called cleanest on the basis of which one of the BOD values given below :

In the following reaction the reason why meta-nitro product also formed is :

'A' and 'B' in the following reactions are :

What is the correct sequence of reagents used for converting nitrobenzene into m-dibromobenzene?

The diazonium salt of which of the following compounds will form a coloured dye on reaction with $$\beta$$-Naphthol in NaOH?

Which of the following reaction/s will not give p-aminoazobenzene?

Correct statement about the given chemical reaction is :

Carbylamine test is used to detect the presence of primary amino group in an organic compound. Which of the following compound is formed when this test is performed with aniline?

An amine on reaction with benzensulphonyl chloride produces a compound insoluble in alkaline solution. This amine can be prepared by ammonolysis of ethyl chloride. The correct structure of amine is :

A. Phenyl methanamine B. N,N-Dimethylaniline C. N-Methyl aniline D. Benzenamine Choose the correct order of basic nature of the above amines.

In the above chemical reaction, intermediate ''X'' and reagent/condition ''A'' are :

Which of the following reactions DOES NOT involve Hoffmann bromamide degradation?

Which of the following is least basic?