Benzene ring in phenol is expected to give the characteristic substitution or replacement reactions i.e. halogenation, nitration, sulphonation, alkylation etc. In these reactions, the attacking reagent is electrophile. The phenolic group activates the ortho and para positions in the ring due to conjugation. Disubstitution reactions are quite fast as the electron density in the ring has increased considerably. Phenols do not respond to nucleophilic substitution reactions as it is influenced by phenolic group.
Picric acid is very strong acid due to presence of:"

Arrange the following nucleophiles in the decreasing order of their attacking strength :
(A) \(C _6 H _5 COO ^{-}\)
(B) \(CH _3 CH _2 CH _2 COO ^{-}\)
(C) \(CH _3 CH _2 CH _2 CH _2 S^{-}\)
(D) \(CH _3 CH _2 CH _2 CH _2 O ^{-}\)
Choose the correct answer from the options given below :

Select the correct statements from the following:
(A) Mn show the highest oxidation state in first transition series elements.
(B) Titanium (II) is more stable than titanium (III) and titanium (IV).
(C) Scandium does not exhibit variable oxidation states.
(D) Zn form complexes with only (II) oxidation state.
Choose the correct answer from the options given below:

Which compound of transition metal is used as a catalyst in the Contact Process?

Read the passage carefully and answer the questions
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.
The major product in the reaction of anisole with bromine in ethanoic acid, is :

Cr is reducing but Mn is oxidising in nature although both have \(\text{d}^1\) configuration. It is due to the reason that Cr configuration changes from

Which of the following compounds will show highest acidic strength?

The relation \(R\) in the set \(\{1,2,3\}\) given by \(R=\{(1,1),(2,2),(3,3),(1,2),(2,3)\}\) is:

Which one of the following plants will have many ovules in their gynoecium?

A compound is formed by two elements P and Q. Atoms of the element Q (anions) make hcp lattice and those of element P (cations) occupies \(\frac{1}{8}\)th of the tetrahedral voids. What is the formula of the compound?

A pure silicon crystal has \( 5 \times 10^{28} \text{ atoms m}^{-3} \). It is doped by 2 ppm concentration of pentavalent arsenic. The number of holes are: (Consider \( n_i = 1.5 \times 10^{16} \text{ m}^{-3} \))

About ______ the first cellular forms of life appeared on earth.

A current of 15 A in the primary coil of a circuit is reduced to zero at a uniform rate in \( 10^{-6} \, \text{s} \). If the coefficient of the Mutual Inductance is 4 H, what is the Induced emf in secondary coil?