What are the substances which mimic the natural chemical messengers?

Which of the following compounds is soluble in benzene but almost insoluble in water?

In which of the following reactions, \(\mathrm{MgO}\) is not formed?

Match List-I with List-II
\(\begin{array}{|c|l|l|l|}\hline & \text{List-I (Reaction)} & & \text{List-II (Enzyme)} \\ \hline \text{A.} & \begin{array}{l} \text{Hydrolysis of starch to} \\ \text{maltose}\end{array} & \text{I} & \text{Diastase} \\ \hline \text{B.} & \begin{array}{l} \text{Conversion of proteins} \\ \text{to peptides} \end{array} & \text{II} & \text{Pepsin} \\ \hline \text{C.} & \begin{array}{l} \text{Hydrolysis of sucrose} \\ \text{to glucose and fructose}\end{array} & \text{III} & \text{Invertase} \\ \hline \text{D.} & \text{Glucose to ethanol} & \text{IV} & \text{Zymase} \\ \hline\end{array}\)
The correct answer is

\(A\) and \(B\) are ideal gases. The molecular weights of \(A\) and \(B\) are in the ratio of \(1: 4\). The pressure of a gas mixture containing equal weights of \(A\) and \(B\) is \(P\) atm. What is the partial pressure (in atm) of \(B\) in the mixture?

Which of the following is an example for chain-growth polymer?

The compound which exhibits both geometrical and optical isomerism is

At \(\mathrm{T}(\mathrm{K}), \mathrm{K}_{\mathrm{c}}\) value for \(\mathrm{AO}_2(\mathrm{~g})+\mathrm{BO}_2(\mathrm{~g}) \rightleftharpoons \mathrm{AO}_3(\mathrm{~g})+\mathrm{BO}(\mathrm{g})\) is 16. In a closed 1 L flask, one mole each of \(\mathrm{AO}_2, \mathrm{BO}_2, \mathrm{AO}_3\) and BO are taken and heated to \(\mathrm{T}(\mathrm{K})\). What is the concentration (in \(\mathrm{mol} \mathrm{L}^{-1}\) ) of \(\mathrm{AO}_3\) at equilibrium?

. A bullet of mass \(0.01 \mathrm{~kg}\) travelling at a speed of \(500 \mathrm{~ms}^{-1}\) strikes a block of mass \(2 \mathrm{~kg}\) which is suspended by a string of length \(5 \mathrm{~m}\). The centre of gravity of the block is found to rise a vertical distance of \(0.1 \mathrm{~m}\). What is the speed of the bullet after it emerges from the block?

The foci of the ellipse \(9 x^2+25 y^2=225\) are

The maximum value of \(12 \sin x-5 \cos x+3\) is

The line \(x-2 y-3=0\) cuts the parabola \(y^2=4 \mathrm{ax}\) at the points P and Q . If the focus of this parabola is \(\left(\frac{1}{4}, k\right)\), then \(P Q=\)

If \(\lim _{x \rightarrow 0} \frac{\cos 2 x-\cos 4 x}{1-\cos 2 x}=k\), then \(\lim _{x \rightarrow k} \frac{x^k-27}{x^{k+1}-81}=\)