$A$ nucleus of an element $_{84}X^{202}$ emits an $\alpha$-particle first,a $\beta$-particle next,and then a gamma photon. The final nucleus formed has an atomic number:

Sulphide ores of metals are usually concentrated by froth floatation process. Which one of the following sulphide ores offers an exception and is concentrated by chemical leaching?

Let $A = \{ x: x \in R, |x| < 1 \}$ and $B = \{ x: x \in R, |x - 1| \ge 1 \}$. If $A \cup B = R - D$,then the set $D$ is:

When acetaldehyde is reacted with $LiAlH_4$,what is the product formed?

The length of the $x$-intercept made by the pair of lines $2x^2 + xy - 6y^2 - 2x + 17y - 12 = 0$ is

Dry air is passed through a solution containing $10 \ g$ of solute and $90 \ g$ of water,and then it is passed through pure water. The loss in weight of the solution is $2.5 \ g$ and the loss in weight of the pure solvent is $0.05 \ g$. Calculate the molecular weight of the solute.