What is the minimum quantity (in grams) of $methyl$ iodide required for preparing one mole of ethane by Wurtz reaction? (Atomic weight of iodine $= 127$)

If the vectors $a \hat{i}+\hat{j}+\hat{k}$,$\hat{i}+b \hat{j}+\hat{k}$,and $\hat{i}+\hat{j}+c \hat{k}$ $(a \neq 1, b \neq 1, c \neq 1, a \neq b \neq c)$ are coplanar,then the value of $\frac{1}{1-a}+\frac{1}{1-b}+\frac{1}{1-c}$ is:

If $x$ is real,then the minimum value of $y = \frac{x^2-x+1}{x^2+x+1}$ is

The oxide of a metal contains $40 \%$ of oxygen. The valency of the metal is $2$. What is the atomic weight of the metal?

Boric acid is $NOT$ used in which of the following?

The sum of all the solution $(s)$ of the equation $\sin^{-1} 2x = \cos^{-1} x$ is