What product is obtained when ethyl hydrogen sulphate is heated with an excess of alcohol at $410 \, K$?

The concentration of an organic compound in chloroform is $6.15 \ g$ per $100 \ mL$ of solution. $A$ portion of this solution in a $5 \ cm$ polarimeter tube causes an observed rotation of $-1.2^{\circ}$. What is the specific rotation of the compound?

Which of the following salts gives a white precipitate with $AgNO_3$ solution and dilute $H_2SO_4$ solution,and also gives a green flame test?

If a normal chord at a point $t$ on the parabola $y^2=4ax$ subtends a right angle at the vertex,then $t^2$ equals to

Zirconium phosphate $[Zr_3(PO_4)_4]$ dissociates into three zirconium cations of charge $+4$ and four phosphate anions of charge $-3$. If molar solubility of zirconium phosphate is denoted by $S$ and its solubility product by $K_{sp}$,then which of the following relationships between $S$ and $K_{sp}$ is correct?

If the chord of contact of tangents from a point on the circle $x^2 + y^2 = r_1^2$ to the circle $x^2 + y^2 = r_2^2$ touches the circle $x^2 + y^2 = r_3^2$,then $r_1, r_2, r_3$ are in: