Hello! Such questions are answered by using concept from chemical equilibrium and pH formulas. First, you are required to find the concentration of H+ or H3O+ ions at concentration by using chemical equilibrium secondly you will calculate pH for particular H+ concentration by using -log [H+] formula. Below the equation shows the reaction of butanoic acid with water producing butyrate and hydronium ions. Initially when the reaction is at time = 0 no H3O+ is produced, then, reaction starts and equilibrium is attained at which unknown (x) amount of H3O+ is formed. This unknown concentration is calculated as shown below (i don't know much maths so, i use online calculator). When concetration of H3O+ is in hand then you can simply calculate pH.
Also, before starting the calculation you should find out Molarity of given acid by following method,
Molarity = moles ÷ dm³
Molarity = (mass ÷ M. Mass) ÷ dm³
M. Mass of Butyric acid = 88 g/mol
So, Molarity = (8.7 g ÷ 88 g/mol) ÷ 1 dm³
Molarity = 0.0988 mol/dm³
Answer:
B. PhCHO
Explanation:
Every organic group shows a characteristic IR absorption at certain wavelength . With the help of these absorption spectra we can identify the group present on organic molecules .
The wave number of 2710 cm⁻¹ is absorbed by aldehyde bond stretching .
The wave number of 1705 cm⁻¹ is shown by conjugated aldehyde . So the most likely compound among given compounds is PhCHO .
The density is 4 g/cm³ or 4000 kg/m³.
Density = mass/volume = 12 g/3 cm³ = 4 g/cm³
The measurement of 4 g/cm³ is already in <em>SI units</em>.
In SI <em>bas</em>e units,
Density = (4 g/1 cm³) × (1 kg/1000 g) × (100 cm/1 m)³ = 4000 kg/m³
The molecule<span> is symmetric, a tetrahedron. Thus, the 4 </span>polar bonds <span>cancel each other out.</span>