Tag: science & technology

Quizzes (551) Questions (11015)

Questions Related to science & technology

Multiple choice general knowledge science & technology

When an iron nail gets rusted, iron oxide is formed

  1. without any change in the weight of the nail

  2. with decrease in the weight of the nail

  3. with increase in the weight of the nail

  4. without any change in colour or weight of the nail
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When iron rusts, it combines with oxygen to form iron oxide (Fe2O3·xH2O), which adds oxygen atoms to the original iron. Since oxygen has mass, the rusted nail weighs more than the pure iron nail.

Multiple choice general knowledge science & technology

Among the various allotropes of carbon,

  1. coke is the hardest, graphite is the softest

  2. diamond is the hardest, coke is the softest

  3. diamond is the hardest, graphite is the softest

  4. diamond is the hardest, lamp black is the softest
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Diamond is the hardest known natural material due to its strong covalent bonds in a 3D tetrahedral structure. Graphite is extremely soft because its layers are held by weak van der Waals forces, allowing them to slide easily.

Multiple choice general knowledge science & technology

Heavy water is

  1. deuterium oxide

  2. PH7

  3. rain water

  4. tritium oxide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heavy water (D2O) is deuterium oxide - water where the hydrogen atoms are replaced by deuterium, hydrogen's heavy isotope containing one proton and one neutron. It's about 10% denser than regular water.

Multiple choice general knowledge science & technology

The chemical (ethyl merceptan) added to the otherwise odourless LPG cooking gas for imparting a detectable smell to the gas is a compound of

  1. bromine

  2. fluorine

  3. chlorine

  4. sulphur
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ethyl mercaptan (ethanethiol, C2H5SH) is a sulfur-containing organic compound added to odorless LPG in trace amounts. The sulfur atoms give it the extremely strong, unpleasant smell that alerts users to gas leaks.

Multiple choice general knowledge science & technology

Non stick cooking utensils are coated with

  1. Teflon

  2. PVC

  3. black paint

  4. polystyrene
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Teflon (polytetrafluoroethylene or PTFE) is the standard non-stick coating used on cookware due to its high heat resistance, chemical inertness, and extremely low friction surface. PVC is used for pipes and insulation, black paint is simply a coloring agent, and polystyrene is a brittle plastic used for packaging - none of these provide non-stick properties.

Multiple choice general knowledge science & technology

Monazite is an ore of

  1. titanium

  2. zirconium

  3. iron

  4. thorium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Monazite is a phosphate mineral that is the primary commercial source of thorium, along with containing rare earth elements. It is not an ore of titanium (which comes from ilmenite/rutile), zirconium (zircon), or iron (hematite/magnetite).

Multiple choice general knowledge science & technology

Carbon, diamond and graphite are together called

  1. allotropes

  2. isomers

  3. isomorphs

  4. isotopes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Allotropes are different structural forms of the same element in the same physical state. Carbon exists as diamond, graphite, and amorphous carbon - all allotropes with different arrangements of carbon atoms. Isomers are molecules with the same formula but different structure, isomorphs are crystals with similar form but different composition, and isotopes are atoms with different numbers of neutrons.