If $\left|\begin{array}{cc}x & 2 \\ 18 & x\end{array}\right|=\left|\begin{array}{cc}6 & 2 \\ 18 & 6\end{array}\right|,$ then $x$ is equal to

Let $p = (x + 4y)\,a + (2x + y + 1)\,b$ and $q = (y - 2x + 2)\,a + (2x - 3y - 1)\,b,$ where $a$ and $b$ are non-collinear vectors. If $3p = 2q,$ then the values of $x$ and $y$ are:

Amongst $LiCl$,$RbCl$,$BeCl_{2}$,and $MgCl_{2}$,the compounds with the greatest and the least ionic character,respectively,are

The number of solutions of the system of equations $2x + y - z = 7$, $x - 3y + 2z = 1$, and $x + 4y - 3z = 5$ is

Which of the following is the strongest Lewis acid?

The collector plate in an experiment on the photoelectric effect is kept vertically above the emitter plate. $A$ light source is turned on and a saturation photocurrent is recorded. An electric field is then switched on which has a vertically downward direction.