Which element is responsible for the crimson red color in fireworks?

Diborane reacts with ammonia under different conditions to give a variety of products. Which one among the following is not formed in these reactions?

If the circle $x^2 + y^2 = a^2$ intersects the hyperbola $xy = c^2$ in four points $P(x_1, y_1), Q(x_2, y_2), R(x_3, y_3), S(x_4, y_4)$,then:

An ideal gas is expanding such that $PT^2 = \text{constant}$. The coefficient of volume expansion of the gas is (in $/T$)

If $m$ and $n$ are respectively the order and degree of the differential equation of the family of parabolas with origin as its focus and $X$-axis as its axis,then $mn-m+n=$

Observe the following reaction: $2A + B \longrightarrow C$. The rate of formation of $C$ is $2.2 \times 10^{-3} \ mol \ L^{-1} \ min^{-1}$. What is the value of $-\frac{d[A]}{dt}$ (in $mol \ L^{-1} \ min^{-1}$)?