Benzaldehyde reacts with ammonia to form

Which of the following metal carbides is known as a methanide?

The absolute value of the tangent of the difference of the angles made by the lines $4x^2 - 24xy + 11y^2 = 0$ with the $X$-axis is

Solid $BeH_2$ and solid $BeCl_2$ differ in

$A$ telescope has an objective lens of focal length $144\, cm$ and an eyepiece of focal length $6\, cm$. Find the magnifying power of the telescope for normal adjustment.

If there is an error of $\pm 0.04 \text{ cm}$ in the measurement of the diameter of a sphere, then the approximate percentage error in its volume, when the radius is $10 \text{ cm}$, is