What is percentage atom economy during conversion of reactant to product if formula weight of reactants is \(246 \mathrm{u}\) and of product is \(123 \mathrm{u}\) ?

A first order reaction is \(75 \%\) completed in 60 minutes, the time required for it's \(50 \%\) completion is.

A gas is allowed to expand in an insulated container against a constant external pressure of \(2.5 \mathrm{~atm}\) from \(2.5 \mathrm{~L}\) to \(4.5 \mathrm{~L}\), the change in internal energy of the gas in joules is

How many moles of acetic acid is obtained in the reaction when one mole glucose is treated with excess acetic anhydride?

For an ideal gas, the heat of reaction at constant pressure and constant volume are related as

Calculate the standard enthalpy change for reaction,
\(\begin{aligned}
& \mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}_{(\ell)}+3 \mathrm{O}_{2(\mathrm{~g})} \rightarrow 2 \mathrm{CO}_{2(\mathrm{~g})}+3 \mathrm{H}_2 \mathrm{O}_{(\ell)} \\
& \text {If,}\\
& \text {} \begin{aligned}
\Delta_{\mathrm{f}} \mathrm{H}^{\circ}\left(\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}\right) & =-280 \mathrm{~kJ} \mathrm{~mol}^{-1} \\
\Delta_{\mathrm{f}} \mathrm{H}^{\circ}\left(\mathrm{CO}_2\right) & =-390 \mathrm{~kJ} \mathrm{~mol}^{-1} \\
\Delta_{\mathrm{f}} \mathrm{H}^{\circ}\left(\mathrm{H}_2 \mathrm{O}\right) & =-285 \mathrm{~kJ} \mathrm{~mol}^{-1}
\end{aligned}
\end{aligned}\)

Solutions \(A, B, C\) and \(D\) are respectively \(0 \cdot 2\) M urea, \(0 \cdot 10\) M \(\mathrm{NaCl}, 0.05 \mathrm{M} \mathrm{BaCl}_{2}\) and \(0.05 \mathrm{M} \mathrm{AlCl}_{3}\).
All solutions are isotonic with each other except

Velamen tissue is useful for absorption of water vapours from atmosphere in _________ .

In Young's double slit experiment, the slits are separated by 0.6 mm and screen is placed at a distance of 1.2 m from slit. It is observed that the tenth bright fringe is at a distance of 8.85 mm from the third dark fringe on the same side. The wavelength of light used is

The polarising angle of transparent medium is ' \(\theta\) '. Let the speed of light in the medium be ' \(V\) '. Then the relation between ' \(\theta\) ' and ' \(V\) ' is [ \(\mathrm{C}=\) velocity of light in air]

Which from following species acts as base, according to Bronsted-Lowry theory? \(\mathrm{HCl}+\mathrm{NH}_3 \rightleftharpoons \mathrm{NH}_{4(\mathrm{aq})}^{+}+\mathrm{Cl}_{(\mathrm{aq})}^{-}\)

Bactericidal antibiotic is

A proton and alpha particle are accelerated through the same potential difference. The ratio of the de-Broglie wavelength of proton to that of alpha will be (mass of alpha particle is four times mass of proton.)