Answer: Option (a) is the correct answer.
Explanation:
Enthalpy is defined as the total amount of heat present in a system.
When there is bond formation in a chemical reaction then it means energy is released. Hence, the reaction is exothermic in nature and 
< 0 or negative.
On the other hand, when breaking of bonds occurs then energy is absorbed by the system. Hence, the reaction is endothermic in nature and > 0 or positive.
Thus, in the given reaction 
, the state is changing from liquid to solid.
This means atoms are coming close to each other and hence, there is occurrence of bond formation. As a result, energy will be released to the surroundings.
Hence, we can conclude that H < 0 for the given reaction.
Answer: Paramagnetism is most easily observed in the salts of some of the first row transition metals (manganese through nickel). The se metal ions have unpaired electrons in degenerate d orbitals as predicted by Hund's rule and thus exhibit paramagnetism.
Explanation: METALS ARE ELECTRONS
AND PARAMAGNETIC OBSERVES SALT FORST ROWS ONLY
Answer:
The biological sample that pregnancy tests use to detect pregnancy is urine
Answer:
Explanation:
Use the periodic table to identify the noble gas that would be included in the noble-gas notation for each of the following elements.
Si:
Fr:
Hg:
V:
Answer: The correct answer is Heterogeneous mixture
Explanation:
Heterogeneous mixture are those mixture in which:
- Substance is distributed in non uniform manner.
- Two distinct layers are formed
Thus when water and dirt are mixed together it results in the formation of a heterogeneous mixture and after sometimes two different layers will be observed.
Hence, in the bottle there is a heterogeneous mixture of water and dirt.
