This experiment have a component of \'independent investigation\' . You must fin

ID: 1059420 • Letter: T

Question

This experiment have a component of 'independent investigation' . You must find relevant chemicals of interest for identification. Please designing identification procedures by doing research about these chemicals using online resources and books

Experiments 4-6: Identification of Common Chemicals Introduction The main purpose of this and the following two experiments is to familiarize yourself with some of the properties of common chemicals. In addition, you will gain experienc with several physical and chemical methods that are commonly used in chemical analysis. Finally, by developing your own scheme for identifying the various chemicals, you will begin to learn how to plan an analysis logically and will gain some appreciation for the method of scientific investigation Your objective for this experiment is to develop a series oftests that will allow you to identify the chemicals listed in Table 1. You must find properties for each chemical that allow you to distinguish it from all of the others in that table. This experiment is divided into three parts. In focuses on assortment of chemicals and methods of identification are examined. Part B distinguishing the chemicals from the others. c is a test to be taken by all students in the last lab session of this course. If you keep careful records of your results in your laboratory notebook, you will be able to devise a complete scheme for the identification of any of the chemicals as soon as you have tested the last of them. Then you only need to try out your scheme to see that it works well. Safety Precautions Review the safety rules on pages 5 and 8-9 of this manual Wear goggles at all times. Never taste any chemical. smell chemicals by fanning some of the vapors toward your nose and then only when specifically directed do so your instructor. Never smell a reaction mixture when it is it is reacting. If you must touch chemicals or if you inadvertently get chemicals on immediately with soap and large volumes of running water. Report any contact with chemicals to your Use small quantities of chemicals as directed. Compare the amounts you take with those in labeled test tubes prepared by your instructor or weigh the chemicals. Stay at a distance from a reaction mixture while it is being heated. Never use anything but a glass stirring rod to mix chemicals. If you can, mix chemicals by gently tapping the side of a test tube with your finger. Have your instructor demonstrate this technique.) Never bring large quantities of liquid near an open flame. 52

Explanation / Answer

1) to test given metals we will add cold water

(i) Magnesium will show reaction

(ii) no reaction with Aluminium or Zinc

(iii) very slow reaction of aluminium with acid and fast reaction of Zn with acid [HCl]

The rest of the test are being summarized in the table

S.No

Chemical

Test

Reacts with cold water to give bubbles on surface

With acid: few bubbles but will take time

With acid: fast reaction, bubbles of colourless gas

Black in colour

Yellow in colour

NaCl

Soluble in water with no pH change [yellow orange color in flame tes]

NH4Cl

Soluble in water with pH less than 7

CaCl2

Soluble in water, will give brick-red colour in flame test

SrCl2

Will give red / crimson colour in flame test

Cu(NO3)2.3H2O

Blue crystals

Ni(NO3)2.6H2O

emerald green solid

NaHCO3

Soluble in water and gives brisk effervescence with HCl

CaCO3

Insoluble in water and gives brisk effervescence with HCl

K2CO3

Gives violet blue colour in flame test

FeS

Reacts with Hcl giving rotten egg smell (due to H2S evolution)

KAl(SO)43

White transparent solid When heated get liquefied

CuSO4

White powder gives blue coloured solution when dissolved in water

CuSO4.H2O

Blue coloured powder

Na2SO3

KMnO4 soaked filter paper turns brown in presence of HCl

Na2B4O7

Crystalline white solide which turns transparent liquid on heating

K2CrO4

With AgNO3 forms Red-brown ppt of Ag2CrO4

C12H22O11

Charring on heating

HNO3 (3M)

pH = 3

HCl(6M)

pH = 6

H2SO4(6M)

pH = 5.7

HC2H3O2(6M)

pH = more than 6

NaCl (3M)

pH =7

NH3(6M)

pH = more than 7

CH3OH

Spirit like smell

C2H5OH

Typical alcohol smell

(CH3)2CO

Highly volatile

C6H14

No test with acid / base. Insoluble in water. Soluble in benzene

C2H4(OH)2

High viscous liquid

Cr(NO3)3

Green in colour turns dark violet when hydrated

Cr2O3

Dark green in colour, turns brown on heating and restore green colour on cooling

Li2CO3

Flame test gives red colour

LiCl

With AgNO3 gives white ppt