Answer: Option (c) is the correct answer.
Explanation:
Generally, when we move from top to bottom in a group then there occur increase in the number of electrons due to which there will also occur increase in the number of shells.
As atomic size is the distance between the nucleus and valence shell of an atom. Hence, more is the number of shells present in an atom more will be its atomic radius.
Thus, we can conclude that the statement atomic radius of elements in a group decreases as you go from top to bottom, is generally FALSE.
The answer is D. Fertilizer and vinegar
Answer: Most people think positively about chemistry. Chemistry has had a good impact on the world, such as the impact of renewable energy, clean water, and technology.
Explanation:
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Answer:
2.28 × 10^-3 mol/L
Explanation:
The equation for the equilibrium is
CN^- + H2O ⇌ HCN + OH^-
Ka = 4.9 × 10^-10
KaKb = Kw
4.9 × 10^-10 Kb = 1.00 × 10^-14
Kb = (1.00 × 10^-14)/(4.9 × 10^-10) = 2.05 × 10^-5
Now, we can set up an ICE table
CN^- + H2O ⇌ HCN + OH^-
I/(mol/L) 0.255 0 0
C/(mol/L) -x +x +x
E/(mol/L) 0.255 - x x x
Ka = x^2/(0.255 - x) = 2.05 × 10^-5
Check for negligibility
0.255/(2.05 × 10^-5) = 12 000 > 400. ∴ x ≪ 0.255
x^2 = 0.255(2.05 × 10^-5) = 5.20 × 10^-6
x = sqrt(5.20 × 10^-6) = 2.28 × 10^-3
[OH^-] = x mol/L = 2.28 × 10^-3 mol/L
