Which of the following solutions have the same number of hydrogen ions as in 50 cm3 of 0.1 mol dm-3 sulphuric acid?

I 100 cm3 of 0.1 mol dm-3 hydrochloric acid
II 50 cm3 of 0.2 mol dm-3 nitric acid
III 100 cm3 of 0.2 mol dm-3 sulphuric acid
IV 50 cm3 of 0.1 mol dm-3 phosphoric acid

Word equation for k(s) +h2o(l) yield koh (aq) + h2

An alloy contains 66 g of pure zinc. what is the percentage of zinc in the alloy? express your answer to two significant figures and include the appropriate units.

In what way do investigations build scientific knowledge? the results of investigations lead to questions that cannot be tested. they reflect the opinions and social values of scientists, ensuring valid information. the results of investigations lead to new questions, which lead to new investigations. they are not influenced by the research of earlier scientists, so they are able to address gaps in understanding.i