Which of the following statements about the standard hydrogen electrode is not correct?

The standard hydrogen electrode is an electrode used as a reference for measuring the standard electrode potential of other half-cells. One of the given statements about the standard hydrogen electrode is incorrect. Let's look at each statement to identify the incorrect one. - The hydrogen gas is at a pressure of 1 atmosphere: This statement is correct. The hydrogen gas is bubbled over the platinum electrode at a pressure of 1 atmosphere. - A solution containing 1 mol dm-3 of H+ (aq) ions is used: This statement is correct. The hydrogen electrode is dipped into a solution containing 1 mol dm-3 of H+ ions. - A platinum electrode is used: This statement is correct. The standard hydrogen electrode consists of a platinum electrode coated with finely divided platinum black. - The temperature is kept at 20 °C: This statement is incorrect. The temperature of the standard hydrogen electrode should be 25 °C (298 K), not 20 °C. Therefore, the statement that is not correct is "The temperature is kept at 20 °C."