The fluoride which is most soluble in water is

When a wire of length $10 \ m$ is subjected to a force of $100 \ N$ along its length,the lateral strain produced is $0.01 \times 10^{-3} \ m$. The Poisson's ratio was found to be $0.4$. If the area of cross-section of the wire is $0.025 \ m^2$,its Young's modulus is

Let $A = \{x \in R, x \neq 0, -4 \leq x \leq 4\}$ and $f: A \rightarrow R$ be defined by $f(x) = \frac{|x|}{x}$ for $x \in A$. Then,the range of $f$ is

$A$ sulphide ore is first converted into its oxide before reduction. This is done because

The reagent used for converting acetylene to oxalic acid is

If $x > 0$ and $x^y = e^{x-y}$,then $\frac{dy}{dx}$ is equal to