How to prepare for ISEET 2014:- “Learn the fundamental concepts of Physics, Chemistry and Mathematics” what is the meaning of learning the concepts.

How to prepare for ISEET 2014

“Learn the fundamental concepts of Physics, Chemistry and Mathematics”: - everybody says that “learn fundamental concepts to crack any competitive exams, learn basic concepts. Don’t just remember, or mugup the things.” but do u know what is exactly meaning of “learning the fundamentals and basics” Let’s see what is the meaning of learning the concepts.

For example if you are learning about equivalent no., equivalent wt. Normally most students think that always equivalent wt. Of H₂SO₄ is 49. If you are thinking the same, means your concepts also not clear. It is not always 49.

Let’s clear the concept

 Equivalent wt = molecular wt. / n factor

Now n factor for acids = basicity of acids (no. Of total replaceable H⁺ ion)

Because there are two H in H₂SO₄ are replaceable. Its n factor is 2.

So eq. Wt = 98/2 =49

But it is always not true. n factor also depend on chemical reaction. If in any reaction H₂SO₄ only donate 1 H⁺ ion and gets converted into HSO₄^- for example :-

NaOH + H₂SO₄ →NaHSO₄ + H₂O

In the above reaction H₂SO₄  only donating 1 H⁺. So here n factor for H₂SO₄ is one 1. So eq.wt = 98/1= 98 in this reaction

But in the following reaction

2 NaOH + H₂SO₄ →Na₂SO₄ + 2H₂O

H₂SO₄ donate its all 2 H⁺ ion and gets converted into SO₄^-2 ion. So in this reaction n factor for H₂SO₄ is 2. So eq. Wt of H₂SO₄ in this reaction = 98/2 = 49.

Because H₂SO₄ have total 2 H⁺ to donate. So generally we assume that it is donating its all two H⁺. Hence generally we consider n factor for H₂SO₄ is two. But if in the question there is any reaction of H₂SO₄ is given then carefully see the reaction whether it is donating 1 or two H⁺. According to that your ans. of eq.wt. of H₂SO₄ would be 98 or 49. But if there is no such reaction of H₂SO₄ is given then we assume that H₂SO₄  is donating its all two H⁺ ion so n factor is assumed two and eq.wt is 49.