Answer:
Since with LiBr no precipitation takes place. So, Ag+ is absent
When we add Li2SO4 to it, precipitation takes place.
Ca2+(aq) + SO42-(aq) ----> CaSO4(s) ...Precipitate
Thus, Ca2+ is present.
When Li3PO4 is added, again precipitation takes place.Reaction is:
Co2+(aq) + PO43-(aq)---->Co3(PO4)2(s) ... Precipitate
A. Ca2+ and Co2+ are present in solution
B. Ca2+(aq) + SO42-(aq) ----> CaSO4(s)
C. 3Co2+(aq) + 2PO43-(aq)---->Co3(PO4)2(s)
<h2>5060 have three significant figures : Explanation given below </h2>
Explanation:
Significant figures
The significant figures (also known as the significant digits and decimal places) of a number are digits that possess certain meaning .
It includes all digits except: zeros
Rules to find significant figures
1.All non-zero digits are considered significant. For example, 23 has two significant figures.
2.Zeros in between two non-zero digits are significant: like in 202.1201 has seven significant figures.
3.Zeros to the left of the significant figures are not significant. For example, .000021 has two significant figures, zeros have no value .
4.Zeros to the right of the significant figures are significant.
That is the reason in number 5060 , it has 3 significant figures .
From the question you will find that:
one capsule of tamiflu is obtained from 2.6 g of star anise.
1 capsule = 2.6 g tamiflu
? capsules = 155 g tamiflu
by cross multiplication =

= 59 capsules
Answer : The concentration of Si in kilograms is, 
Explanation :
As we are given that, the concentration of Si in an Fe-Si alloy is 0.25 wt% that means:
Weight of Si = 0.25 g = 0.00025 kg
Weight of Fe = 100 - 0.25 = 99.75 g = 0.09975 kg
Density of Si = 
Density of Fe = 
Now we have to calculate the concentration in kilograms of Si per cubic meter of alloy.
Concentration of Si in kilograms = 
Concentration of Si in kilograms = 
Now put all the given values in this expression, we get:
Concentration of Si in kilograms = 
Concentration of Si in kilograms = 
Thus, the concentration of Si in kilograms is, 
The concentration of the solution is 4.25 M
Explanation
molarity=moles/volume in liters
moles = mass/molar mass
molar mass of HF = 19 + 1 = 20 g/mol
moles is therefore = 17.0 g/ 20 g/mol = 0.85 moles
volume in liters = 2 x10^2ml/1000 = 0.2 liters
therefore molarity = 0.85/0.2 = 4.25 M