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# A drop (0.05ml) of 12M HCl is spread over a thin sheet of aluminum foil (thickness 0.10mm and density of Al=2.70g/ml).Assuming whole of the HCl is used to dissolve Al,what will be the maximum area of hole produced in foil?

$(a)\;0.1cm^2\qquad(b)\;0.2cm^2\qquad(c)\;0.3cm^2\qquad(d)\;0.4cm^2$

Meq of Al=Meq of HCl
$\qquad\quad\;\;=12\times 0.05=0.6$
Weight of Al=$\large\frac{0.6\times 9}{1000}$$=0.0054g Volume of Al foil=\large\frac{0.0054}{2.7}$$cm^3$
$\qquad\qquad\qquad=0.002cm^3$
Area$\times$ thickness=volume
Area=$\large\frac{0.002}{0.01}$$=0.02cm^2$
Hence (b) is the correct answer.