Answer:
C) 2 Na + 2 H2O → 2 NaOH + H2.
Explanation:
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In this case, according to the given chemical reactions, it is possible to firstly understand that a single displacement reaction is characterized by the presence of a single element as the first reactant and a compound as the second one, thus, yielding a compound as the first product and a single element as the second one.
In such a way, according to the given choices, it possible to note that C) 2 Na + 2 H2O → 2 NaOH + H2 is the only one with the aforementioned condition as the element at the reactants side is Na and at the products side is H2.
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Answer: The final temperature is 
Explanation:

As we know that,

.................(1)
where,
q = heat absorbed or released
= mass of lead = 50 g
= mass of water = 75 g
= final temperature = ?
= temperature of lead = 
= temperature of water = 
= specific heat of lead = 
= specific heat of water= 
Now put all the given values in equation (1), we get
![50\times 0.11\times (T_{final}-373)=-[75\times 1.0\times (T_{final}-273)]](https://tex.z-dn.net/?f=50%5Ctimes%200.11%5Ctimes%20%28T_%7Bfinal%7D-373%29%3D-%5B75%5Ctimes%201.0%5Ctimes%20%28T_%7Bfinal%7D-273%29%5D)

Therefore, the final temperature of the mixture will be 279.8 K.
Answer:
I am so confused about this i am so sorry but i cant there is to much going on
Explanation:
Answer:
b. Add a few drops of one of the layers to a test tube containing 1 mL of water. Shake the test tube to determine the solubility of the layer in water
Explanation:
Option a is not true, it depends on the compound being extracted.
Option c is not true, although most of the solvents used in extractions have lower boiling point than water there are exceptions, for example toluene.
Option d is not true. Again most of the solvents used in extractions are less dense than water, there are many exceptions, for example chloroform, so for equal volumes the chloroform layer will weigh more.
Option b. is the correct one.
One will test the miscibility of the layer in water. If it inmiscible then one would know is the organic layer. If it is the aqueous layer then it will completely be miscible.