The acidity of a solution is typically measured by pH. A pH of 7 is neutral. A pH below 7 is acidic, and a pH above 7 is basic, or alkalotic. Normal blood pH is 7.4. Having acid in the blood means that the pH is below 7.4, and excessive protons may be found in the blood.
The number of chromosomes in the secondary spermatocyte are 23 but each chromosome having two chromatids, while the chromosomes in the spermatid are also 23 but each chromosome is made up of one chromatid.
Yes, a regular body cell has 23 pairs of chromosomes, so 46 chromosomes in total. 23 chromosomes come from your mom in the form of the haploid gamete (egg), and 23 from your father in a haploid gamete (sperm). Once the sperm fertilizes the eggs, it becomes a diploid zygote. I think you have the second part a little mixed up.