MCQ
The product obtained when silica reacts with hydrogen fluoride is
- A$SiF_4$
- ✓$H_2SiF_6$
- C$H_2SiF_4$
- D$H_2SiF_3$
The reactions are as follows:
$\mathrm{SiO}_{2}+4 \mathrm{HF} \rightarrow \mathrm{SiF}_{4}+2 \mathrm{H}_{2} \mathrm{O}$
$3 \mathrm{SiF}_{4}+4 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{H}_{2} \mathrm{SiF}_{6}+\mathrm{H}_{4} \mathrm{SiO}_{4}$
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$(A)$ Sulphanilic acid $(B)$ Picric acid $(C)$ Aspirin $(D)$ Ascorbic acid
$(At. No. Ti = 22, V = 23, Cr = 24, Mn=25)$
| Run | $[A]/mol\,L^{-1}$ | $[B]/mol\,L^{-1}$ | Initial rate of formation of $D/mol\,L^{-1}\,min^{-1}$ |
| $I.$ | $0.1$ | $0.1$ | $6.0 \times 10^{-3}$ |
| $II.$ | $0.3$ | $0.2$ | $7.2 \times 10^{-2}$ |
| $III.$ | $0.3$ | $0.4$ | $2.88 \times 10^{-1}$ |
| $IV.$ | $0.4$ | $0.1$ | $2.40 \times 10^{-2}$ |
Based on the above data which one of the following is correct?