3 - b) weight decreases
4 -a) 50 kg as mass is same everywhere
5 - b) 200 dynes
Lithium metals reacts slowly with water to form a colourless solution of lithiums hydroxide (LiOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic, but the reaction is slower than that of sodium (immediately below lithium in the periodic table)
Salt water offers the least electrical resistance.
<u>Explanation:</u>
Least electrical resistance indicates that any material which readily allows the electric current through itself, and shows more conductivity.
Here pure water doesn't contain any ions, so it is a bad conductor.
Wood and glass are also bad conductors of electricity.
Salt water contains ions, which conducts electricity which means it shows least electrical resistance.
