Question

What is the work done when 50g of iron reacts with hydrochloric acid in an open beaker at ${25}^{o}C$ ?

• A. - 22.12 joule
• B. + 22.12 joule
• C. +2212.22 joule
• D. -2212.22 joule

Answer 1

The correct option is D -2212.22 joule

Molar mass of $Fe=56g$

Given mass of $Fe=50g$

As we know that,

$\text{No. of moles}=\frac{\text{Mass}}{\text{Molar mass}}$

Therefore, number of moles of $Fe$ used-

$n=\frac{50}{56}=0.893\text{moles}$

As we know that,

$w=-P\Delta V=-nRT[\because PV=nRT]$

Given $T=25℃=(25+273)=298K$

$\therefore w=-0.893\times 8.314\times 298=-2212.47\text{joule}\approx -2212.22\text{joule}$

Hence the work done will be $-2212.22\text{joule}$.