Formula: NA2S2O3. Valency: 2
Answer: (C)
The frequency increases as the wavelength decreases
Explanation:
The relation between the frequency and wavelength of a wave is
Frequency = 1 / Wavelength
The Frequency of electromagnetic wave is inversely proportional to the wavelength. So, as the frequency increases, the wavelength of the wave decreases and vise-versa.
The frequency of a wave is number of complete cycles passing a particular point per second. Its S.I unit is Hertz whereas the wavelength of a wave is the distance between two consecutive crest and trough in meters.
So, on increasing the frequency of a wave, there will be more number of the cycles of wave per second which will decrease the distance between the consecutive crest and trough i.e wavelength.
When The balanced equation is:
2Al + 3CuCl2 ⇒3 Cu + 2AlCl3
So, we want to find the limiting reactant:
1- no. of moles of 2Al = MV/n = (Wt * V )/ (M.Wt*n*V) = Wt / (M.Wt *n)
where M= molarity, V= volume per liter and n = number of moles in the balanced equation.
by substitute:
∴ no. of moles of 2Al = 0.2 / (26.98 * 2)= 0.003706 moles.
2- no.of moles of 3CuCl2= M*v / n = (0.5*(15/1000)) / 3= 0.0025 moles.
So, CuCl2 is determining the no.of moles of the products.
∴The no. of moles of 3Cu = 0.0025 moles.
∴The no.of moles of Cu= 3*0.0025= 0.0075 moles.
and ∵ amount of weight (g)= no.of moles * M.Wt = 0.0075 * M.wt of Cu
= 0.0075 * 63.546 =0.477 g
*A & B*
Answers A & B are not possible, as Hydrogen “bonds” are intermolecular forces and do not actually involve transfer or sharing of electrons.
*C & D*
Viscosity and surface tension are not the answer as they are not specific enough to the question.
*E*
Polarity of water molecules is the correct answer, as water molecules are highly polar. The partial positive of the Hydrogen on one water molecule is highly attracted to the partial negative of the Oxygen (due to its lone pairs) on another water molecule.
