Therefore option c , i.e. The substances in both test tubes are reactive only at high temperatures. is the only statement which is NOT supported by the student's observations.
<h3>What is the reaction between Magnesium and Hydrogen ?</h3>
Magnesium reacts with hydrochloric acid to produce hydrogen gas
Mg (s) + 2 HCl (aq) → MgCl₂ (aq) + H₂ (g)
In this reaction, the magnesium and acid are gradually used up , which can be seen in the test tube 2 .
A chemical reaction is taking place in Test tube 2 ,
Hydrogen gas is released in test tube 2 ,
Energy is released in the reaction involving hydrochloric acid and we can see in test tube 2 the reaction is going on
therefore option C i.e. The substances in both test tubes are reactive only at high temperatures. is the only statement which is NOT supported by the student's observation.
To know more about the chemical reaction between Magnesium and Hydrogen and this test.
brainly.com/question/19062002
#SPJ4
The added KI does not have any impact
The reaction invovles Titration of vitaminc ( Ascorbic acid)
ascorbic acid + I₂ → 2 I⁻ + dehydroascorbic acid
the excess iodine is free reacts with the starch indicator, forming the blue-black starch-iodine complex.
This is the endpoint of the titration. since alreay excess KI is added ( the source of Iodine), it does not have an influence.
Answer B
Hope this helps!
Answer: 480 kJ of energy is released when 3.5 mol of 
reacts.
Explanation:
The balanced chemical reaction is:
Thus it is given that the reaction is exothermic (heat energy is released) as enthalpy change for the reaction is negative.
1 mole of on reacting gives = 137 kJ of energy
Thus 3.5 moles of on reacting gives = 
of energy
Thus 480 kJ of energy is released when 3.5 mol of reacts.
