The compound used as a primary standard in volumetric analysis is :

Elements of group-15, 16 and 17 form compounds with hydrogen with general formula MH3, \(H 2 M\) and HX (called hydrogen halides). Stability of these hydrides, along with M-H bond strength and basic nature decreases down the group. Boiling point of these hydrides mainly depends on the strength of their inter molecular forces.
Bond angle (HMH) among hydrides of group-16 decreases down the group because:

In the following sequence of reactions :
CH3–CH(NH2) - CH3 $\xrightarrow{HNO_2}$[A] $\xrightarrow{Oxidation}$[B] $\xrightarrow{H^{+}/H_{2}O}$ CH3MgBr
[C] The compound [C] is :

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Replacement of a hydrogen atom in a hydrocarbon by an alkoxy or carboxyl group yields a class of compounds known as ethers. Ethers are classified as symmetrical or unsymmetrical on the basis of groups attached to the oxygen atoms. Diethyl ether, a symmetrical ether, has been widely used as an inhalation anesthetic. Ethers can be prepared by acid catalyzed intermolecular dehydration of alcohols and Williamson's synthesis. Acid catalyzed dehydration of alcohols is not generally preferred as it gives a mixture of elimination and substitution products. In Williamson's synthesis, an alkyl halide is allowed to react with sodium alkoxide. Ethers containing substituted Alkyl groups may also be prepared by this method. The C-O bond in ether is weakly polar and is cleaved under drastic conditions with excess of hydrogen halides. In electrophilic substitution, the alkoxy group deactivates the aromatic ring and directs the incoming group to ortho and para positions.
Which type of ether is anisole ?

If cell constant doubles and resistance of cell is halved, what will be new resistivity?

The total number of ions produced from the compound \(\left[ Cr \left( NH _3\right)_6\right] Cl _3\) in aqueous solution will be:

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Haloalkanes undergo nucelophilic substitution reactions owing to the polarity of CX bond. The nucleophile reacts with the haloalkane on the carbon possessing a partial positive charge holding the halogen atom. The halogen atom X is replaced by a nucleophile. Depending on the kinetics and mode of bond breaking, the mechanism can be either SN1 or SN2 reaction. The rate of SN1 reaction is governed by the stability of carbocation and in SN2 reaction, the rate of reaction is governed by steric factor. Chirality is the main factor in both SN1and SN2. In SN1 reaction, the chirality of alkyl halide is accompanied by racemization of the product, while in SN2 reaction, the product is characterized by inversion of configuration. The structure of alkyl halide and the nature of the solvent also governs the mechanism of the substitution.
Hydrolysis of 2-Chlorobutane will result in formation of

An external voltage is applied across a diode such that the n-side is positive and the p-side is negative. As a result,
(A) the barrier height decreases
(B) the barrier height increases
(C) the depletion region widens
(D) the depletion region width decreases
(E) no change in barrier height
Choose the correct answer from the options given below:

In the metallurgy of Al , purified \(Al _2 O _3\) is mixed with \(Na _3 AlF _6\) or \(CaF _2\). The role of \(Na _3 AlF _6\) or \(CaF _2\) is to:

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Organic compounds derived from NH3 by replacing one or more H-atoms with alkyl or aryl groups will form primary, secondary and tertiary amines. The common methods which include their preparations are reduction of nitro group, amide group and nitrile group, Gabriel phthalimide synthesis and ammonolysis of alkyl halides. Amines are basic in nature due to the presence of a lone pair of electrons on the nitrogen atom. Important chemical properties of amines include acylation, alkylation and their interaction with nitrous acid. There are various tests which can distinguish different types of amines from each other, for e.g. carbylamine test, Hinsberg's test, coupling reaction etc. Another important class of compounds which can be derived from primary amines is azo compounds. These compounds are intensely colored and widely used as dyes in textile, leather and food industries.
Conversion of nitro group into primary amine is preferred using

Which one of the following is not a parasitic adaptation?

In forward bias and in reverse bias, respectively, the width of the depletion layer of a p-n junction

If a line makes angles \(\alpha, \beta, \gamma\) with the positive directions of the coordinate axes, then the value of \(\cos 2 \alpha+\cos 2 \beta+\cos 2 \gamma\) is