CHAPTER 4- Chemical Reactions Used in Titrimetry

Question 1

• determination of N or M of solution
• accomplished SECONDARY STANDARD or PRIMARY STANDARD

Answer 1

Standardization

Question 2

Use of another standard solution

Answer 2

Secondary Standard

Question 3

Use of known purity substance

Answer 3

Primary Standard

Question 4

• The weight of substance chemically equivalent to 1 mL of standard solution express in mg/mL
  Titer = N x mEq. wt.

Answer 4

Titer

Question 5

2 types of Volumetric Apparatus

Answer 5

1.To Deliver
2. To Contain

Question 6

Burets, Pipets

Answer 6

To Deliver

Question 7

Volumetric Flask, Graduated Cylinder

Answer 7

To Contain

Question 8

• Graduated glass tubes of uniform bore throughout the whole length
• Closed at the bottom by glass or stopcock
• Read at lower meniscus (for clear solutions)

Answer 8

Burets

Question 9

2 Types of Buret

Answer 9

1. Mohr
2. Geissler

Question 10

• for bases; a length of tubing connects a separate tip; economical

Answer 10

Mohr

Question 11

• built in stopcock; expensive but more accurate

Answer 11

Geissler

Question 12

2 Types of Titration

Answer 12

1. Direct Titration
2. Residual Titration (Indrect, Back Titration)

Question 13

one titrant used, one volumetric solution

Answer 13

Direct Titration

Question 14

two titrants, two volumetric solutions

Answer 14

Residual Titration

Question 15

1st VS - added in excess
2nd VS - used to titrate the excess
- used whenever the direct titration is not practicable
- for compounds which react too slowly with the titrant and with poor solubility used if volatile substances are involved

Answer 15

Residual Titration

Question 16

process of repeating the procedure but omitting the sample

Answer 16

Blank Determination

Question 17

4 Chemical Reactions Used in Titrimetry

Answer 17

1. Neutralization
2. Precipitation
3. Oxidation-Reduction
4. Complexation

Question 18

• The reactions must proceed to completion.
• The reaction must proceed in a stoichiometric manner.
• A suitable endpoint detecting device (indicators, electrode) is available.
• For direct titration, the reaction must be rapid so a sharp endpoint is achieved.

Answer 18

4 Requirements must be met if the reaction is to be used

Question 19

• a chemical process in which an acid reacts with a base
  Ex: HCl + NaOH –> NaCl + H2O
  Products: Water and Salt

Answer 19

Neutralization

Question 20

• are complex organic compounds used to:
• determine the end point
• determine the pH
• indicate that a desired change in pH has been effected

Answer 20

Indicators

Question 21

-Use 3 drops of indicator TS unlesss otherwise directed
- Strong Acid + Strong Base - use MO, MR, PHP
- Strong Acid + Weak Base - use MR
- Weak Acid + Strong Base - use PHP
- Weak Acid + Weak Base - no indicator, never been titrated

Answer 21

Rules for the Use of Indicators

Question 22

• Strong Acid - HCl, HNO3, H2SO4, H3PO4
• Strong Base - NaOH, KOH
• Weak Acid - Acetic Acid, Oxalic Acid
• Weak Base - NH3, Alanine (C3H5O2NH2), Methylamine (CH3NH2), Pyridine (C5H5N)

Answer 22

Examples of Rules for the Use of Indicators

Question 23

direct or residual titrimetric analysis of acids using a base

Answer 23

Alkalimetry

Question 24

Sample: Acid
Titrant: Base

Answer 24

Direct Titration of Alkalimetry

Question 25

direct or residual titrimetric analysis of base using a acid

Answer 25

Acidimetry