In the nitration of benzene using a mixture of conc. H₂SO₄ and conc. HNO₃, the nitrating species is

The presence or absence of hydroxyl group on which carbon atom of sugar differentiate RNA and DNA :

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The term vitamin was coined from the word vital +amine since the earlier identified compounds had amino groups. Later work showed that most of them didn't contain amino groups. They are very essential for the body. They has to be taken various diet or in the form of medicines also.
Vitamins are classified into two groups depending upon their solubility in water or fat.
Fat soluble vitamins are soluble in fat and oils but insoluble in water. They are stored in liver and adipose (fat storing) tissues Water-soluble vitamins are soluble in water. These must be supplied regularly in diet because they are readily excreted in urine and cannot be stored in our body.
Which vitamin is known as Riboflavin?

We have four aqueous solution labelled as :
(A) 0.1 M NaCl
(B) 0.01 M NaCl
(C) \(0.01 M BaCl _2\)
(D) 0.01 M Sucrose
Choose the correct increasing order of Van't Hoff factor from the options given below :

Name the reaction when carboxyclic acids having an a -hydrogen are halogenated at the a-position on treatment with chlorine in the presence of a small amount of red phosphorus.

What is the common name of the given compound?

What is the oxidation state of Pt in \(\left( PtF _5\right)_4\) ?

The pyramid that always remains upright is :

Which of the following technique(s) is/are NOT useful in early detection of cancer?
(A) X-rays radiography
(B) Computed tomography
(C) Widal test
(D) Biopsy and histopathological studies
(E) Magnetic Resonance Imaging
Choose the correct answer from the options given below:

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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.
When ethanol is dehydrated in the presence of H₂SO₄, at 443 K and 413 K respectively, the products formed are

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The degeneracy of the \(d\) orbitals has been removed due to ligand electron-metal electron repulsions in the octahedral complex to yield three orbitals of lower energy, \(t_2\), set and two orbitals of higher energy, \(e_g\) set. This splitting of the degenerate levels due to the presence of ligands in a definite geometry is termed as crystal field splitting and the energy separation is denoted by \(\Delta_0\). Thus energy of the two \(e_g\), orbitals will increase by \((3 / 5) \Delta_0\) and that of three \(t_{2 g}\) will decrease by \((2 / 5) \Delta_0\). The crystal field splitting \(\Delta_0\) depends upon the field produced by the ligand and charge on the metal ion. Some ligands are able to produce strong fields, in which case the splitting will be large, whereas others produce weak fields and consequently result in small splitting of \(d\) orbitals. Relative magnitude of crystal field splitting energy \(\Delta_0\) and pairing energy, \(P\) (energy required for electron pairing in a single orbital) determine the formation of low spin ( \(\Delta_0>P\) ) or high spin ( \(\Delta_0<P\) ) complex. In tetrahedral coordination entity formation, the \(d\)-orbital splitting is inverted and is smaller as compared to the octahedral field splitting. The crystal field theory attributes the colour of the complex to \(d-d\) transition of the electron. The colour of the coordination compounds depends on the crystal field splitting. In the absence of ligand, crystal field splitting does not occur and hence the substance is colourless.
Choose the correct statement from the following:

If \(A=\left[\begin{array}{cc}2 & -3 \\ -4 & 7\end{array}\right]\) and \(2 A^{-1}=K I-A\), where \(K\) is a real number and \(I\) is the identity matrix of order 2 , then the value of \(K\) is :

Which of the following argument supports the conservation of biodiversity from the below statement:
"Waking up to a Bulbul's song in the morning"