MCQ
The coinage metals are
- AIron, Cobalt, Nickel
- BCopper and Zinc
- ✓Copper, Silver and Gold
- DGold and Platinum
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The half-life period is independent of the concentration of zinc at constant $pH$. For the constant concentration of $Zn$, the rate becomes $100$ times when $pH$ is decreased from $3\, to\, 2$. Identify the correct statements $(pH = -\log [H^{+}])$
$(A)$ $\frac{{dx}}{{dt}}\, = k{[Zn]^0}{[{H^ + }]^2}$
$(B)$ $\frac{{dx}}{{dt}}\, = k{[Zn]}{[{H^ + }]^2}$
$(C)$ Rate is not affected if the concentraton of zinc is made four times and that of $H^+$ ion is halved.
$(D)$ Rate becomes four times if the concentration of $H^+$ ion is doubled at constant $Zn$ concentration