Question

Which of the following statement is incorrect?
(i) The standard enthalpy of reaction is the enthalpy change for a reaction when all the participating substances are in their standard states.
(ii) The standard state of a substance at a specified temperature is its pure form at 1 bar.
(iii) The standard state of solid iron at $298\, K$ is pure iron at $1 atm$
(iv) Standard conditions are denoted by adding the superscript $\ominus$ to the symbol $\Delta H\, e . g .,-\Delta H^{\ominus}$

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (iii) only
• D. (iv) only

Answer 1

Answer: (C)

Standard state of solid iron at $298\, K$ is pure iron at 1 bar. The standard conditions are denoted by adding the superscript $\ominus$ to the symbol $\Delta H e . g .,-\Delta H^{\ominus}$.