if 10ml of h2so4 is mixed with 10ml of mgoh2 of the same conc., the resultant solution will give which colour with universal indicator?? I wrote the answer as yellow because it will be slightly acidic due to magnesium hydroxide being a mild base
Answers
The resultant solution will give yellow colour with universal indicator.
• H₂SO₄ is a strong acid, while Mg(OH)₂ is a weak base.
• For complete neutralization to take place between a strong acid and a weak base of equal concentration, the volume of the base added must be more than that of the acid.
• In this case, the volume of both H₂SO₄ and Mg(OH)₂ is 10 ml each, so, complete neutralisation will not take place.
• Mg(OH)2, being weak in nature, will not completely dissociate into 2OH- ions.
• Only one OH- ion will dissociate from one molecule of Mg(OH)₂, which can neutralise only one H+ ion from H₂SO₄.
• Consequently, the salt produced will be MgHSO₄. It can be shown with the help of a reaction as follows :
Mg(OH)₂ + 2H₂SO₄ → Mg(HSO₄)₂ (acidic salt) + 2H₂O
• Due to the presence of an H+ ion in it, the salt MgHSO₄ will be slightly acidic in nature.
• Further, on being tested with universal indicator, the salt gives yellow colour as it is the characteristic property of universal indicator to produce yellow colour on being tested with a weakly acidic solution.