Calcium hydride on hydrolysis forms

The major product of the following reaction is

An insulated container contains $4 \, moles$ of an ideal diatomic gas at temperature $T$. Heat $Q$ is supplied to this gas,due to which $2 \, moles$ of the gas are dissociated into atoms,but the temperature of the gas remains constant. Then:

If $y(x)$ is the solution of the differential equation $(x + 2)\frac{dy}{dx} = x^2 + 4x - 9, x \ne -2$ and $y(0) = 0$,then $y(-4)$ is equal to

If $A(2,-1)$ and $B(6,5)$ are two points,the ratio in which the foot of the perpendicular from $P(4,1)$ to $AB$ divides $AB$ is:

The apparent frequency of a sound wave as heard by an observer is $10\%$ more than the actual frequency. If the velocity of sound in air is $330 \, m/s$,then:
$(i)$ The source may be moving towards the observer with a velocity of $30 \, m/s$
$(ii)$ The source may be moving towards the observer with a velocity of $33 \, m/s$
$(iii)$ The observer may be moving towards the source with a velocity of $30 \, m/s$
$(iv)$ The observer may be moving towards the source with a velocity of $33 \, m/s$