50   10. a weak acid with an initial ph of 3.2 was titrated with a strong base. 15 ml of 0.1 m naoh was added to the acid to reach the equivalence point at a ph of 8.6. what would you expect the approximate ph of the analyte to be after the first 5 ml of 0.1 m naoh was added? 8.6 3.4 5.1 7.2

Answer : Option C) 5.1

If we consider any weak acid and strong base titration. We usually observe that the pH initially rises quite fast then remains constant during the buffer region before rising rapidly to the end point.

So, if 5 mL of NaOH is considered to be the one third of the way to the endpoint, then after the initial rise which will be more than 3.4 and reaching to the buffer region before rising to the endpoint.

Now, if endpoint has pH of 8.6 a buffer region around 5 is a good but the acid could be acetic acid which has similar pH endpoints with the pKa of 4.74 - so buffer region around 5 will be the good condition.

And hence pH of 5.1 is the most probably the right answer.

5.1 would be the clostest answer

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

i'm assuming that the correct answer is indeed the first one/ "a"..