Water that does not lather easily with soap is called:
A. Distilled water
B. Soft water
C. Rain water
D. Hard water
Answer: Option D
Solution (By JKSSB Mock Tests)
Hard water contains dissolved Ca²⁺ and Mg²⁺ ions which react with soap to form insoluble scum, preventing lather. Soft water lathers readily. Distilled water is pure (soft). Rainwater is naturally soft but may dissolve CO₂ and become slightly acidic.
Explanation:
Marie Curie, along with her husband Pierre, conducted pioneering research on radioactivity (a term she coined). In 1898, they discovered two new radioactive elements: polonium (named after her native Poland) and radium. She was the first woman to win a Nobel Prize and the only person to win in two different scientific fields (Physics and Chemistry).
Explanation:
Flammability describes how a substance reacts with oxygen to burn, which is a chemical change. Boiling point, density, and melting point are physical properties because they can be observed without changing the chemical identity of the substance. Chemical properties are only observed during a chemical reaction.
Explanation:
Graphite is used in electrodes (due to electrical conductivity) and as a moderator in nuclear reactors (to slow down neutrons). It is chemically stable and can withstand high temperatures. Diamond is an insulator. Fullerene is a nanomaterial. Charcoal is used as adsorbent and fuel. Graphite blocks are used in RBMK reactors (like Chernobyl) and in advanced gas-cooled reactors.
No comments yet. Be the first to start the discussion!