Chemistry Answers

What is the pH of a 2.62 x 10 ^-1 M NaNO₂ solution? NB the pKa for HNO₂ = 3.153.

1)0.58

2)13.42

3)8.29

4)12.13

5)1.87

What is the pH of a 2.62 x 10 ^-1 M hypochlorous acid (HOCl) solution? NB the pKa for HOCl = 7.542.

1)13.42

2)7.54

3)4.06

4)10.48

5)0.58

What is the pH of a 3.45 x 10 ^-1 M Ba(OH)₂ solution?

1)12.54

2)13.54

3)0.16

4)0.46

5)13.84

6)12.84

Malic acid (C₄H₆O₅) is one of the alpha hydroxy acid which is naturally found in apples.The reaction of HCl with sodium maleate malic acid and sodium Chlorite is according to the following reaction

HCl + C₄H₅O₅H = C₄H₆O₅ +NaCl

You have to prepare a maleate buffer, (Ka=3.908 × 10^-4) using sodium maleate (M.W.=178.05 g/mol) and 0.200 M HCl. HOw many millimeters of HCl should you add to 250.00 mL of 0.300 M sodium maleate to produce a buffer solution of pH 3.37?

Ca(HCO3)2 (s) --><-- CaO(s) + 2CO2(g) + H2O(g) DHrxn<0

Increasing the temperature of the above reaction will

a. increase the pressure in the tank

b. decrease the amount of Ca(HCO3)2(s) in the flask

c. increase the concentration of CO2(g)

d. decrease the amount of gas in the flask

Which of the following occurs when a reaction in a solution is at equilibrium and more product is added to the solution?

a. Equilibrium shifts to produce more product

b. The reaction will stop

c. Equilibrium shifts to produce more reactant

d. No change will occur

50.00 cm3 of a 1.5784 mol.dm-3 solution of potassium hydroxide is transferred to an empty 700.00 cm3 volumetric flask. This flask is made up to the mark with distilled water and then shaken well. The concentration of the potassium hydroxide in this second flask is:

Calculate the oxidation number of chromium in an unknown salt if the electrolysis of the salt yields 9.71g of chromium at the cathode after a current of 10A is passed through a cell for 1.5 hours.the relative atomic mass of chromium is 52.

What type of reagent is required to convert NO2- to N2?

[1] base

[2] oxidizing agent

[3] acid

[4] reducing agent

[5] precipitating agent

What is the Fischer's structure of (3R)-3-Methylhexane and (4R, 5S)-4,5-diethyloctane