MCQ
$pH$ of a mixture of $1\ M\ HA (pK_a = 4.2)$ and $1\ M\ NaA$ is $4.5$ . In $300\ ml$ of buffer volume of $HA$ is.......$ml$ $[log\, 2 = 0.3]$
- A$200$
- B$150$
- ✓$100$
- D$600$
$\Rightarrow \quad 4.5=4.2+\log \frac{300-x}{x}$
$\Rightarrow \quad 0.3=\log \frac{300-x}{x}$
$\Rightarrow \quad \log 2=\log \frac{300-x}{x}$
$\Rightarrow \quad 2=\frac{300-x}{x}$
$\Rightarrow \quad 2 x=300-x$
$\Rightarrow \quad 3 x=300 \Rightarrow x=100\, \mathrm{ml}$
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| List$-I$ | List$-II$ |
| $(I)$ $XeF_4$ | $(A)$ See-saw |
| $(II)$ $I_3^-$ | $(B)$ Tetra hedral |
| $(III)$ $XeO_2F_2$ | $(C)$ Bond angle $90^o$ |
| $(IV)$ $SO_4^{2-}$ | $(D)$ Linear |