Which one of the following is used as piezoelectric material?

Which of the following reactions are not feasible?
I. \(\mathrm{CH}_3 \mathrm{CH}=\mathrm{CH}_2 \frac{\mathrm{HCl}}{\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{CO}\right)_2 \mathrm{O}_2} \longrightarrow \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{Cl}\)
II. \(\mathrm{C}_6 \mathrm{H}_6+\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{Cl} \stackrel{\mathrm{AlCl}_3}{\longrightarrow} \mathrm{C}_6 \mathrm{H}_5 \mathrm{CH}\left(\mathrm{CH}_3\right)_2\)
III. \(\mathrm{CH}_3 \mathrm{CHClCH}_2 \mathrm{Cl} \underset{\Delta}{\stackrel{\mathrm{KOH}}{\longrightarrow}} \mathrm{CH}_3 \mathrm{C} \equiv \stackrel{+}{\mathrm{CH}}\)
IV. \(\mathrm{CH}_3 \mathrm{CH}=\mathrm{CHCH}_3 \stackrel{\mathrm{KMnO}_4 / \mathrm{H}^{+}}{\longrightarrow} \mathrm{CH}_3 \mathrm{COOH}\)

Identify the correct equation relating \(\Delta H, \Delta U\) and \(\Delta T\) for 1 mole of an ideal gas from the following ( \(\mathrm{R}=\) gas constant)

Which of the following sequences is the correct order of the size of species?

Identify the correctly matched pairs
i. \(\quad \mathrm{TiO}\) - pigment industry
ii. \(\mathrm{MnO}_2\) - dry battery cells
iii. \(\mathrm{Cu} / \mathrm{Ni}\) alloy - UK 'copper' coins

At \(T(\mathrm{~K})\), copper (atomic mass \(=635 \mathrm{u}\) ) has fcc unit cell structure with edge length of \(x Å\). What is the approximate density of \(\mathrm{Cu}\) in \(\mathrm{g} \mathrm{cm}^{-3}\) at that temperature?
\(\left(N_A=6.0 \times 10^{23} \mathrm{~mol}^{-1}\right)\)

The number of octahedral and tetrahedral holes respectively present in a hexagonal close packed ( \(h c p)\) crystal of ' \(X\) ' atoms are

\[
\begin{aligned}
& \text { If the } \\
& a x^2+2 h x y+b y^2+2 g x+2 f y+c=0
\end{aligned} \text { equation }
\]
represents a pair of straight lines, then the square of the distance of their point of intersection from the origin is

Observe the following molecules.
${\mathrm{PCl}}_5,{\mathrm{BrF}}_5,{\mathrm{ClF}}_5,{\mathrm{PF}}_5,{\mathrm{ClF}}_3,{\mathrm{XeF}}_4,{\mathrm{XeF}}_2,{\mathrm{IF}}_5$
The number of molecules having square pyramidal geometry from the above is

The sum of moments of all the particles in a system about its center of mass is always______

In a \(\triangle \mathrm{ABC}\), if \(\sin ^2 \mathrm{~B}=\sin \mathrm{A}\) and \(2 \cos ^2 \mathrm{~A}=3 \cos ^2 \mathrm{~B}\), then the triangle is

If \(\omega\) is a complex cube root of unity, then \(\sum_{r=1}^9 r(r+1-\omega)\left(r+1-\omega^2\right)=\)

If the roots of the equation \(x^3-13 x^2+\mathrm{K} x-27=0\) are in geometric progression then \(\mathrm{K}=\)