MCQ
Cathode rays have
- AMass only
- BCharge only
- CNo mass and charge
- ✓Mass and charge both
Cathode rays are stream of electrons that are negatively charged particles. Cathode rays travel in straight lines from the cathode. The ratio of $e / m$ for a cathode ray is fixed at $1.758820 \times 10^{11} \,C / kg$. It is equal to the ratio of $e / m$ for an electron.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.


$\frac{1}{2}{P_4}(s) + 3C{l_2}(g) \to 2PC{l_3}(l)\,;$ $\Delta H=-635 \,kJ$
$PC{l_3}(l) + C{l_2}(g) \to PC{l_5}(s)\,;$ $\Delta H=-137\, kJ$
The value of heat of formation of $PCl_5$ is ......$kJ\,mol^{-1}$
| Element | Ionization | enthalpy | $(kJ/mol)$ |
| $1^{st}$ | $2^{nd}$ | $3^{rd}$ | |
| $A$ | $899$ | $1757$ | $14847$ |
| $B$ | $737$ | $1450$ | $7731$ |
Which of the following statements is correct ?