Dissociation reaction of calcium hydroxide can be represented as follows:
<span>Ca(OH)2 (s) ⇄ Ca2+(aq) + 2OH-(aq)
</span>
The solubility product of Ca(OH)2 is mathematically expressed as
Ksp = [Ca2+] [OH-]^2
Given: Ksp = <span>4.68 x 10-6
Now, we know that for aqueous system, pH + pOH = 14
and pOH = -log(OH-)
Thus, [OH-] = </span><span>10^(pH - 14)
</span>∴ Ksp = [Ca2+] [10^(pH - 14)]^2 = [Ca2+] [10^(2.pH - 28)]
∴ [Ca2+] = Ksp/10^(2.pH - 28)
= Ksp 10^(28 - 2.pH)
Now, at pH = 4
[Ca2+] = Ksp 10^(28 - 2.pH)
= (4.68 x 10-6) 10^(28 - 2X4)
= 4.68 X 10^14 mol/dm3
At pH = 7,
[Ca2+] = Ksp 10^(28 - 2.pH)
= (4.68 x 10-6) 10^(28 - 2X7)
= 4.68 X 10^8 mol/dm3
At pH = 9
[Ca2+] = Ksp 10^(28 - 2.pH)
= (4.68 x 10-6) 10^(28 - 2X9)
= 4.68 X 10^4 mol/dm3
Answer:
Following is molar solubility of calcium hydroxide at different pH
at pH 4 = 4.68 X 10^14 mol/dm3
at pH 7 = 4.68 X 10^8 mol/dm3
at pH 9 = 4.68 X 10^4 mol/dm3
Individual organisms live together in an ecosystem and depend on one another. ... One category of interactions describes the different ways organisms obtain their food and energy. Some organisms can make their own food, and other organisms have to get their food by eating other organisms.
Answer:
option a, During allotropic transformation, the number of atoms in the material changes.
Explanation:
Allotrops are different crystalline forms of the same element. So, two allotrops of an element have same number of atoms.
for example diamond, graphite, graphene, fullerene are allotropic forms of carbon.
Allpotops differ in physical and chemical properties. So, volume changes during alloptropic transformation. So, statement b is correct.
Allotropic transformation is the transformation of one allotropic form to other therefore, number of atom does not change during allotropic transformation.
Chemical species having same atomic number or same no. of protons are called isotopes. so statement c is correct.
When an electron is added to the neutral element, electronic repulsion increases which lead to the increase in atomic size, So, statement d is also correct.
So among given, option a is incorrect
A chromosome is a tightly coiled X of genetic material that has genes on it.
Hope this helps!
