The product in the following reaction is

It is difficult to separate the ores of Zr and Hf because:

The Gattermann-Koch reaction is used in the industrial preparation of benzaldehyde.
The electrophile involved in this reaction is:

On warming an aldehyde with freshly prepared ammonical silver nitrate solution (Tollen's reagent) a bright silver mirror is produced due to formation of:

The properties which depend on the number of solute particles irrespective of their nature relative to the total number of particles in the solution are called colligative properties. These are relative lowering of vapour pressure of the solvent, depression of freezing point of the solvent, elevation of boiling point of the solvent and osmotic pressure of the solution. All of these properties help in calculating the observed molar mass of the solute.
Determination of osmotic pressure is considered best for the determination of molecular mass of the solute.
A 1 litre solution of glucose containing 36 g of it has an osmotic pressure of 4.98 bar at 300 K .
At the same temperature, the osmotic pressure of the solution is 1.52 bar.
The concentration of the solution at 1.52 bar is :

Match List I with List II

LIST I	LIST II
A. \(\left[ Co \left( H _2 NCH _2 CH _2 NH _2\right)_3\right]_2\left( SO _4\right)_3\)	I. Tetracarbonylnickel(0)
B. \([\text{Ni}(\text{CO})_4]\)	II. Mercury tetrathiocyanatocobaltate(III)
C. \([\text{CoCl}_2(\text{en})_2]^+\)	III. tris(ethane-1,2-diamine)cobalt(III) sulphate
D. \(\text{Hg}[\text{Co}(\text{SCN})_4]\)	IV. Dichloridobis(ethane-1,2-diammine)cobalt(III)

Choose the correct answer from the options given below:

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.
Which type of ether is anisole ?

If in a plano-convex lens, the radius of the convex surface is 10 cm and the focal length is 30 cm. Then the refractive index of the material will be :

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Alcohols are versatile compounds as they can act as both nucleophile and electrophile. They undergo reactions based on cleavage of O-H and C-O bonds. The cleavage of O-H bond reflects the acidic character of alcohols. However they are weaker acids than water, phenol and carboxylic acids. Alkoxide ion formed by loss of proton from the OH group of alcohols reacts with water to form the corresponding conjugate acid - base pair. They act as Bronsted base due to presence of unshared electron pairs on oxygen.Both alcohols and phenol react with carboxylic acids, acid chlorides and anhydrides to form esters. The introduction of acetyl group in alcohols or phenol is known as acetylation. Alcohols react with hydrogen halides to form alkyl halides which form the basis of Lucas test. They also undergo acid catalyzed dehydration to form alkenes. Alcohols can be easily oxidized with variety of oxidizing agents. The nature of the product depends on the type of oxidizing agent and the nature of alcohol.
Pyridinium chlorochromate is used for:

As a biocontrol agents, the ladybird and dragonflies are useful to get rid of -

The non-negative remainder when 7³⁶ is divided by 5 is:

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The coordination compounds are of great importance. These compounds are widely present in the mineral, plants and animal world and are known to play many important functions in the area of analytical chemistry, metallurgy, biological systems, industry and medicine. For example, coordination compounds find use in many qualitative and quantitative chemical analysis. Some important metal extraction and purification make use of complex formation. Hardness of water can be estimated by stable complex formation of Ca\(^{2+}\) and Mg\(^{2+}\)
Wilkinson catalyst used for hydrogenation of alkenes is a complex of ___________.

The force between two electric charges is expressed by the equation : \( F = \frac{kq_1q_2}{r^2} \).
Which of the following is a correct statement ?