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Reimer-Tiemann reaction introduces an aldehyde group, on to the aromatic ring of phenol, ortho to the hydroxyl group. This reaction involves electrophilic aromatic substitution. This is a general method for the synthesis of substituted salicylaldehydes as depicted below.

Question:
Which one of the following reagents is used the above reaction?

The value of \(n\) in the molecular formula \(\mathrm{Be}_n \mathrm{Al}_2 \mathrm{Si}_6 \mathrm{O}_{18}\) is

A decapeptide (molecular weight 796) on complete hydrolysis gives glycine (molecular weight 75), alanine and phenylalanine. Glycine contributes \(47.0 \%\) to the total weight of the hydrolysed products. The number of glycine units present in the decapeptide is

A gas has a compressibility factor of $0.5$ and a molar volume of $0.4 {\mathrm{dm}}^3 {\mathrm{mol}}^{-1}$ at a temperature of $800 \mathrm{K}$ and pressure $\mathrm{x} \mathrm{atm}$. If it shows ideal gas behaviour at the same temperature and pressure, the molar volume will be  $\mathrm{y} {\mathrm{dm}}^3 {\mathrm{mol}}^{-1}$ . The value of$\mathrm{x}/\mathrm{y}$ is _________
[Use: Gas constant, $\mathrm{R}=8\times {10}^{-2} \mathrm{L} \mathrm{atm} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}$ ]

The order of the oxidation state of the phosphorus atom in $H_{3}P{O}_2, H_{3}P{O}_4, H_{3}P{O}_3$ and $H_4{P}_2{O}_6$ is

The species formed on fluorination of phosphorus pentachloride in a polar organic solvent are :

For the process \(\mathrm{H}_2 \mathrm{O}(\mathrm{l})\) (1 bar, \(\left.273 \mathrm{~K}\right) \longrightarrow \mathrm{H}_2 \mathrm{O}(\mathrm{g})\) (1 bar, \(\left.373 \mathrm{~K}\right)\), the correct set of thermodynamic parameters is

The standard enthalpies of formation of $C{O}_2\left(g\right)$ ${\text{, H}}_2\text{O}\left(\mathit{\text{l}}\right)$ and glucose (s) at $25^{\text{o}}C$ are $-\text{400 kJ}/\text{mol}$, $-\text{300 kJ}/\text{mol}$ and $-\text{1300 kJ}/\text{mol}$, respectively. The standard enthalpy combustion per gram of glucose at $25^{\text{o}}C$ is $\left(\Delta H_f^0=-1300kJmo{l}^{-}for\text{glucose}\right)$

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Read the following passage and answer the questions.
Let \(A B C D\) be a square of side length 2 units. \(C_2\) is the circle through vertices \(A, B, C, D\) and \(C_1\) is the circle touching all the sides of square \(A B C D\). \(L\) is the line through \(A\).Question:
If \(P\) is a point on \(C_1\) and \(Q\) is a point on \(C_2\), then \(\frac{P A^2+P B^2+P C^2+P D^2}{Q A^2+Q B^2+Q C^2+Q D^2}\) is equal to

A hydrogen atom, initially at rest in its ground state, absorbs a photon of frequency \(v_1\) and ejects the electron with a kinetic energy of 10 eV . The electron then combines with a positron at rest to form a positronium atom in its ground state and simultaneously emits a photon of frequency \(v_2\). The center of mass of the resulting positronium atom moves with a kinetic energy of 5 eV . It is given that positron has the same mass as that of electron and the positronium atom can be considered as a Bohr atom, in which the electron and the positron orbit around their center of mass. Considering no other energy loss during the whole process, the difference between the two photon energies (in eV ) is \(\qquad\)

A rigid uniform bar $AB$ of length $L$ is slipping from its vertical position on a frictionless floor (as shown in the figure). At some instant of time, the angle made by the bar with the vertical is $\mathrm{\theta }$. Which of the following statements about its motion is correct?

Match the temperature of a black body given in List-$\mathrm{I}$ with an appropriate statement in List-$\mathrm{II}$, and choose the correct option.
[Given: Wien’s constant as $2.9\times {10}^{-3} \mathrm{m}-\mathrm{K}$ and $\frac{hc}{e}=1.24\times {10}^{-6} \mathrm{V}-\mathrm{m}$]

	List-$\mathrm{I}$		List-$\mathrm{II}$
$\mathrm{P}$	$2000 \mathrm{K}$	$1$	The radiation at peak wavelength can lead to emission of photoelectrons from a metal of work function $4 \mathrm{eV}$
$\mathrm{Q}$	$3000 \mathrm{K}$	$2$	The radiation at peak wavelength is visible to human eye
$\mathrm{R}$	$5000 \mathrm{K}$	$3$	The radiation at peak emission wavelength will result in the widest central maximum of a single slit diffraction
$\mathrm{S}$	$10000 \mathrm{K}$	$4$	The power emitted per unit area is $\frac{1}{16}$ of that emitted by a blackbody at temperature $6000 \mathrm{K}$
		$5$	The radiation at peak emission wavelength can be used to image human bones

Let \(z\) be a complex number such that the imaginary part of \(z\) is non-zero and \(a=z^{2}+z+1\) is real. Then a cannot take the value