MCQ
The amorphous form of silica is
- Aquartz
- ✓kieselguhr
- Ccristobalite
- Dtridymite
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

| column $I$ | column $II$ |
| $(A)$ $CO _2( s ) \rightarrow CO _2( g )$ | $(p)$ phase transition |
| $(B)$ $CaCO _3( s ) \rightarrow CaO$ (s) $+ CO _2( g )$ | $(q)$ allotropic change |
| $(C)$ $2 H \bullet \rightarrow H _2( g )$ | $(r)$ $\Delta H$ is positive |
| $(D)$ $P_{\text {(white, solid) }} \rightarrow P_{\text {(red, solid) }}$ | $(s)$ $\Delta S$ is positive |
| $(t)$ $\Delta S$ is negative |
$\mathrm{PF}_5, \mathrm{BrF}_5, \mathrm{PCl}_5,\left[\mathrm{PtCl}_4\right]^{2-}, \mathrm{BF}_3, \mathrm{Fe}(\mathrm{CO})_5$