What are the products formed when phenyl ethyl ether is heated with concentrated $HBr$?

Which of the following taxonomic categories of the housefly is incorrectly matched?

Molar heat capacity $(C_p)$ of water at constant pressure is $75 \ J \ K^{-1} \ mol^{-1}$. The increase in temperature (in $K$) of $100 \ g$ of water when $1 \ kJ$ of heat is supplied to it is

Which of the following is optically active?

Which reagent is commonly used in titration to determine the hardness of water?

Along the $X$-axis,three charges $\frac{q}{2}, -q$ and $\frac{q}{2}$ are placed at $x=0, x=a$ and $x=2a$ respectively. The resultant electric potential at $x=a+r$ (if $a \ll r$) is: ($\varepsilon_0$ is the permittivity of free space)