Question

Given the reaction: $Zn\left(s\right)+2HCl\left(aq\right)\to ZnC{l}_2\left(aq\right)+H_2\left(g\right)$
When a single zinc is used, reaction gets slower than when powered zinc of the same mass is used, why?

• A. The powdered zinc is more concentrated
• B. The single piece of zinc is more reactive
• C. The powdered zinc requires less activation energy
• D. The powdered zinc generates more heat energy
• E. The powdered zinc has a greater surface area

Answer 1

The correct option is E The powdered zinc has a greater surface area

A powdered solid will normally produce a faster reaction than, if the same mass is present as a single lump. The powdered solid has a greater surface area than the single lump. In the reaction, the particles in the liquid $HCl$ collide with the particles in the solid $Zn$. Increasing the surface area of the solid increases the chances of collision taking place.