Which of the following is not a Lewis acid?

Which of the following represents a correct group of Embryophyta?

Which of the following factors does $NOT$ favor the formation of an electrovalent (ionic) bond?

The product of the perpendicular distances from the origin to the pair of straight lines $12x^2+25xy+12y^2+10x+11y+2=0$ is

When ethanol is reacted with $PCl_5$,it gives $A$,$POCl_3$,and $HCl$. The reaction of $A$ with silver nitrite $(AgNO_2)$ gives the major product $(B)$ and $AgCl$. What are $A$ and $B$ respectively?

If the area of the triangle formed by the pair of lines $8x^2 - 6xy + y^2 = 0$ and the line $2x + 3y = a$ is $7$,then $a$ is equal to