Chemistry - Study Mode

[#546] Which of the following is used in dating archaeological findings ?
Correct Answer

(B) 6 14 C

Explanation

Solution: Radiocarbon dating (usually referred to as simply carbon dating) is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e., uncalibrated, radiocarbon ages are usually reported in radiocarbon years “Before Present” (BP), with “present” defined as CE 1950. Such raw ages can be calibrated to give calendar dates. One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites.

[#547] German silver used for making utensils is an alloy of
Correct Answer

(B) Copper, zinc, nickel

Explanation

Solution: Nickel silver, also known as German silver, Argentan, new silver, nickel brass, albata, alpacca, or electrum, is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver is named for its silvery appearance, but it contains no elemental silver unless plated. The name “German silver” refers to its development by 19th-century German metalworkers in imitation of the Chinese alloy known as paktong. Nickel silver first became popular as a base metal for silver-plated cutlery and other silverware, notably the electroplated wares called EPNS (electro-plated nickel silver). It is used in zippers, better-quality keys, costume jewellery, for making musical instruments (e.g., cymbals, saxophones), and is preferred for the track in electrically powered model railway layouts, as its oxide is conductive. It is widely used in the production of coins.

[#548] A fertile soil is likely to have a pH of
Correct Answer

(C) 6-7

Explanation

Solution: A fertile soil is likely to have a pH of 6-7.

[#549] Litmus is obtained from
Correct Answer

(D) Lichen

Explanation

Solution: Litmus, mixture of coloured organic compounds obtained from several species of lichens that grow in the Netherlands, particularly Lecanora tartarea and Roccella tinctorum.

[#550] The pH of lemon juice is expected to be
Correct Answer

(C) Less than 7

Explanation

Solution: The pH level of lemon juice is, 2.00 to 2.60. It varies depending on the lemon. pH expresses different levels of acidity or alkalinity within a solution.