10 most difficult chemistry riddles A list of ten (out of 140) chemistry related questions that are the most often answered incorrectly Chemistry quiz What is the name of the most radioactive isotope on the planet?Polonium 210. 210Po is extremely toxic, with one microgram being enough to kill the average adult (250,000 times more toxic than hydrogen cyanide by weight).210Po was used to kill Russian dissident and ex-FSB officer Alexander V. Litvinenko in 2006,very hard 19% Rad 226Rad 22615%Uranus 235Uranus 23541%Polonium 210Polonium 21019%plutonium 244plutonium 24423%Created by: Tschuka . Statistics based on 409 answers in 2 languages »chemical elements riddles » What is the name of an organic chemical compound used to treat alcoholism?Disulfiram (sold under the trade names Antabuse and Antabus) is a drug used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol (drinking alcohol). very hard 20% AntabusAntabus4%AnticolAnticol21%EsperalEsperal54%DisulfiramDisulfiram20%Created by: Tschuka . Statistics based on 175 answers in 2 languages »diseases riddles » What color is potassium permanganate in a strongly alkaline environment?Green. The permanganate anions are purple. In a strongly alkaline environment, they reduce to green manganese ions MnO4 (2-).very hard 21% BlueBlue16%VioletViolet58%GreenGreen21%Red Red 4%Created by: Tschuka . Statistics based on 112 answers in 2 languages » What does synthesis gas (water gas) consist of?Carbon monoxide (CO) and hydrogen (H2). Water gas is a mixture of carbon monoxide and hydrogen produced from synthesis gas. Synthesis gas is a useful product, but requires careful handling due to its flammability and the risk of carbon monoxide poisoning. The water-gas shift reaction can be used to reduce the carbon monoxide while producing additional hydrogen, resulting in water gas. very hard 20% oxygen (O2) and hydrogen (H2)oxygen (O2) and hydrogen (H2)22%methane (CH4) and water (H2O)methane (CH4) and water (H2O)32%carbon dioxide (CO2) and hydrogen (H2)carbon dioxide (CO2) and hydrogen (H2)24%carbon monoxide (CO) and hydrogen (H2)carbon monoxide (CO) and hydrogen (H2)20%Created by: Tschuka . Statistics based on 2943 answers in 2 languages »water riddles » Which has more calories: table sugar or aspartame?Pretty much the same. Aspartame produces 4 kilocalories of energy per gram when metabolized, sucrose (table sugar) produces 3.9 kilocalories. However, aspartame is approximately 200 times sweeter than sucrose, so it is consumed in much smaller doses. very hard 23% pretty much the samepretty much the same23%table sugar has much more caloriestable sugar has much more calories40%aspartame has much more caloriesaspartame has much more calories16%aspartame has no calories at allaspartame has no calories at all20%Created by: globalquiz.org. Statistics based on 4153 answers in 4 languages »food riddles » What is exactly the pH value of distilled water?It depends on the temperature. Pure water is about 7 at 25 °C; this value decreases with increasing temperatures. At 50 °C, it is 6.55. It is also worth to note, that water that has been exposed to air is mildly acidic, because it absorbs carbon dioxide from the air.very hard 24% 1.01.018%7.07.051%10.010.05%It depends on the temperatureIt depends on the temperature24%Created by: globalquiz.org. Statistics based on 4764 answers in 4 languages »acids riddles » Which of the following is true for the solution with the pH=0?The OH − ion concentration is smaller than the H+ ion concentration. In chemistry, pH is a numeric scale used to specify the acidity or alkalinity of an aqueous solution. It is the negative of the logarithm to base 10 of the activity of the hydrogen ion .Traditionally the pH is being defined as: pH = - log10 [H+], where [H+] it is a H+ ions concentration in mol/dm^3 (M). So if pH = 0 this H+ ions concentration is 1 mol/dm^3 and the solution is strongly acidic.very hard 25% the OH − ion concentration is smaller than the H+ ion concentrationthe OH − ion concentration is smaller than the H+ ion concentration25%the OH − ion concentration is greater than the H+ ion concentrationthe OH − ion concentration is greater than the H+ ion concentration20%the OH − ion concentration is equal of the H+ ion concentrationthe OH − ion concentration is equal of the H+ ion concentration28%Such solution doesn't existSuch solution doesn't exist26%Created by: Paweł Kołodziejczyk. Statistics based on 3328 answers in 2 languages »numbers riddles » What is the third by volume, after nitrogen and oxygen, component of dry air?Argon represents 0.934% of the earth's atmosphere and 1.28% of its mass. Ar-40 is an isotope that makes up the majority of the earth's argon. It is a result of decaying of another elements' unstable isotopes, mainly Potassium-40.very hard 25% carbon dioxidecarbon dioxide52%methanemethane3%ozoneozone18%argonargon25%Created by: Rafał. Statistics based on 3345 answers in 2 languages »atmosphere riddles » What is the name of the phenomenon of faster freezing of warmer water than colder water?Mpemba effect. The Mpemba effect, is the observation that, in some circumstances, warmer water can freeze faster than colder water. There have been reports of similar phenomena since ancient times, although with insufficient detail for the claims to be replicated.very hard 25% Mpemba effectMpemba effect25%Phenomenon of LeidenfrostPhenomenon of Leidenfrost43%Wulff processWulff process13%Maxwell's vitrificationMaxwell's vitrification17%Created by: Tschuka . Statistics based on 146 answers in 2 languages »discoverers riddles » What ions are formed during self-ionization of water?H₃O + and OH-. The self-ionization of water is an ionization reaction in pure water or in an aqueous solution, in which a water molecule, H2O, deprotonates to become a hydroxide ion, OH−. The hydrogen nucleus, H+, immediately protonates another water molecule to form hydronium, H3O+. It is an example of autoprotolysis, and exemplifies the amphoteric nature of water. very hard 28% H₃O + and OH-H₃O + and OH-28%HO₂- and H₂OHO₂- and H₂O18%OH + and H₃O-OH + and H₃O-14%All answers are correctAll answers are correct37%Created by: Tschuka . Statistics based on 516 answers in 2 languages »physics riddles » Play chemistry quiz and see all the questions.