✔ 最佳答案
1.
Slaked lime is Ca(OH)2 solid. The dilute nitric acid is a solution which contains H+(aq) ions. The ionic equation for the reaction is thus:
Ca(OH)2(s) + 2H+(aq) → Ca2+(aq) + H2O(l) …… (1)
You may argue that Ca(OH)2(s) is slightly soluble in water and is then dissociate to give OH-(aq). You may assume that Ca(OH)2 dissolves in the solution to give OH-(aq) ions followed by the reaction with the nitric acid. The ionic equation is then written as:
OH-(s) + H+(aq) → H2O(l) …… (2)
However, Ca(OH)2 is only slightly soluble in water. Besides, reaction (1) is very vigorously and thus reaction (1) would occur before the dissolving of Ca(OH)2. Therefore, many teachers do not accept equation (2).
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2.
The potassium hydroxide used is solid. The dilute sulphuric acid is a solution which contains H+(aq) ions. The ionic equation for the reaction is thus:
2KOH(aq) + H2SO4(aq) → K2SO4(aq) + 2H2O(l) …… (3)
You may also argue that KOH dissolves in the solution to give OH-(aq) ions followed by the reaction with the sulphuric acid. The ionic equation is then written as:
OH-(s) + H+(aq) → H2O(l) …… (4)
However, reaction (3) is very vigorously and thus reaction (3) would occur before the dissolving of Ca(OH)2. Therefore, many teachers do not accept equation (4).
