Answer:
no.it is false.some are useful.like mixture of h2 and O 2 to form water.
Explanation:
The chemical reaction given in the question is as follows -
MnO₄⁻ (aq) + 8H⁺ (aq) + 5e⁻ → Mn²⁺ (aq) + 4H₂O (l)
NO₃⁻ (aq) + 4H⁺ (aq) + 3e⁻ → NO (g) + 2H₂O (l)
As we know , the value for reduction potential are -
Mn²⁺ = + 1.51 V
NO₃⁻ = +0.96 V
From , the data given above , the value of the reduction potential of NO₃⁻ is less than the reduction potential of Mn²⁺ .
Hence ,
NO₃⁻ can not oxidize Mn²⁺ .
<u>Stimulants </u> often cause overactive eye movement
Ans (A)
Stimulants are a class of psychoactive drugs that increase the brain activity. They work by acting on the central nervous system and increase the level of mental alertness and impart heightened cognitive functions. Stimulants like nicotine and cocaine cause overactive eye movement.
Answer: 16.32 g of 
as excess reagent are left.
Explanation:
To calculate the moles :
According to stoichiometry :
2 moles of 
require = 1 mole of
Thus 0.34 moles of will require=
of
Thus is the limiting reagent as it limits the formation of product and is the excess reagent.
Moles of left = (0.68-0.17) mol = 0.51 mol
Mass of 
Thus 16.32 g of as excess reagent are left.
