Imat 2023 Question35

A pH meter is used to test 0.1 mol Lā€“1 aqueous solutions of the following compounds:

CH3COOH

NaCl

H2SO4

Ba(OH)2

HNO3

Which of the following correctly lists these solutions in order of increasing pH?

H2SO4 < HNO3 < CH3COOH < NaCl < Ba(OH)2

H2SO4 has the lowest pH because it is a diprotic acid meaning it releases two moles H+ per mole of dissolved acid molecule.

HNO3 is a monoprotic acid and therefore less acidic.

And CH3COOH (acetic acid) as an organic acid is even less acidic - organic acids are generally less acidic in comparison to inorganic acids.

NaCl is a salt and has no acidic or basic properties, thereby neutral (pH=7).

Ba(OH)2 is basic due to OH- ions in the solution (pH>7). Recall that the elements of the 1st and 2nd group of the periodic table yield basic solutions (create hydroxyl-ions) when they react with water.

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