Decomposition of \(\mathrm{NH}_{3}\) on the surface of platinum has a rate constant of \(2.5 \times 10^{-4} \mathrm{~mol} \mathrm{dm^{-3 } \mathrm { s } ^ { - 1 } \text { at } 3 5 0 \mathrm { K } \text { . The order of }}\) the reaction is

The lowering in vapour pressure is maximum for

Choose the correct metal/ ion from the brackets which ..........
A. has chemical reactivity similar to that of the first few members of the Lanthanoids \((\mathrm{Zn}, \mathrm{Ca}, \mathrm{Fe}, \mathrm{Cu})\).
B. has stable \(4 \mathrm{f}^7\) electronic configuration, but acts as a strong reducing agent and converts to \(\mathrm{M}^{3+}\) state. \(\left(\mathrm{Eu}^{2+}, \mathrm{Ce}^{2+}, \mathrm{Pr}^{2+}, \mathrm{Dy}^{2+}\right)\)
C. is a colorless ion \(\left(\mathrm{Tm}^{3+}, \mathrm{Lu}^{3+}, \mathrm{Gd}^{3+}, \mathrm{Sm}^{3+}\right)\).
D. shows stable +2 oxidation state and is diamagnetic \((\mathrm{Ce}, \mathrm{Sm}, \mathrm{Ho}, \mathrm{Yb})\)

Increasing order of bond order of oxygen and its ions is

Consider the following reaction
Propyne \(+\mathrm{CH}_3 \mathrm{MgBr} \xrightarrow{\text { dry ether }} \mathrm{X}\)
Identify ' \(X\) ' from the following.

Rain water is called acid rain when its pH

When a sulphur sol is evaporated, sulphur is obtained. On mixing with water, sulphur sol is not formed. The sol is

If \(A=\left|\begin{array}{lll}a_{1} & b_{1} & c_{1} \\ a_{2} & b_{2} & c_{2} \\ a_{3} & b_{3} & c_{3}\end{array}\right|\) and \(B=\left|\begin{array}{ccc}c_{1} & c_{2} & c_{3} \\ a_{1} & a_{2} & a_{3} \\ b_{1} & b_{2} & b_{3}\end{array}\right|\) then

What is the velocity of light in vacuum if the velocity of light in a medium of refractive index 1.2 is ' v ' \(\mathrm{ms}^{-1}\) ?

A line \(L_1\) passes through the points \((h, k),(1,2)\) and \((-3,4)\). The points \((4,3)\) and \((h, k)\) lie on the line \(L_2\). Given \(L_1 \perp L_2\) then \((k-h)\) equals to

\(\text { Let } f(x)=\cos ^{-1}(3 x-1) \text {, then domain of } f(x) \text { is equal to }\)

The differential equation of the family of straight lines whose slope is equal to \(y\)-intercept is

Across the 220 V source of internal resistance \(20 \Omega\), how many lamps of \(40 \mathrm{~W}, 100 \mathrm{~V}\) can be connected in parallel so that all the lamps may glow with full brightness.