QUES: Hydrogen gas was first artificially produced in the early 16th century, via the mixing of metals with acids. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, a property which later gave it its name: in Greek, hydrogen means "water-former".

When was hydrogen gas artificially produced for the first time?
What is the answer?
ANS: early 16th century
QUES: Admissions are characterized as "most selective" by U.S. News & World Report. There were 35,099 applications for the undergraduate class of 2020 (entering 2016), and 3,751 (10.7%) were admitted, making Northwestern one of the most selective schools in the United States. For freshmen enrolling in the class of 2019, the interquartile range (middle 50%) on the SAT was 690–760 for critical reading and 710-800 for math, ACT composite scores for the middle 50% ranged from 31–34, and 91% ranked in the top ten percent of their high school class.

For freshman enrolling in the class of 2017, what was the interquartile range on the SAT for math?
What is the answer?
ANS: unanswerable
QUES: Extending the Gregorian calendar backwards to dates preceding its official introduction produces a proleptic calendar, which should be used with some caution. For ordinary purposes, the dates of events occurring prior to 15 October 1582 are generally shown as they appeared in the Julian calendar, with the year starting on 1 January, and no conversion to their Gregorian equivalents. For example, the Battle of Agincourt is universally considered to have been fought on 25 October 1415 which is Saint Crispin's Day.

In the Julian calendar when is the start of the new year?
What is the answer?
ANS:
1 January