CHEMISTRY INVESTIGATORY PROJECT

AIM - TO STUDY THE PRESENCE AND ESTIMATION OF NICKEL IN CHOCOLATES.

YEAR – 2017 - 2018

BY: -

KENDRIYA VIDYALAYA DEPARTMENT OF CHEMISTRY

CERTIFICATE

This is to certify that Master _________________, a student of class XII has successfully completed the research on the project “TO

STUDY THE PRESENCE AND ESTIMATION OF NICKEL IN CHOCOLATES” under the guidance of _________________ (Subject Teacher) during the year 2017-18 in partial fulfillment of Chemistry Practical Examination conducted by AISSCE, New Delhi.

Signature Of Chemistry Teacher Signature of External Examiner

Signature of Principal School Stamp

INDEXCertificate Acknowledgement Introduction Role of Nickel Properties of Nickel Aim Chemical Required Apparatus Procedure Observation Result Conclusion Bibliography

ACKNOWLEDGEMENTIn the accomplishment of this project successfully, many people have best owned upon me their blessings and the heart pledged support, this time I am utilizing to thank all the people who have been concerned with project.Primarily I would thank god for being able to complete this project with success. Then I would like to thank my Chemistry Teacher ____________________, whose valuable guidance has been the ones that helped me patch this project and make it full proof success his suggestions and his instructions has served as the major contributor towards the completion of the project.

Then I would like to thank my parents and friends who have helped me with their valuable suggestions and guidance has been helpful in various phases of the completion of the project. Last but not the least I would like to thank my classmates who have helped me a lot.

INTRODUCTION1. The future of any nation depends on the

health, prosperity and progress of the forthcoming generation. In the present era of industrialization and development, one concern should be the health of the future generation. Children are the most vulnerable age group to any kind of contamination in the food chain. Chocolates and candies/toffees are the favorite food items of children and are often presented to them as token of love and affection from their parents and relatives.

2. Consumption of chocolates and toffees is not limited to a part of society. There are many types of locally made toffees and chocolates available in the market at a cheaper price than known brands. Out of these, only 60–70% has food labels listing ingredients on the wrappers. The most common ingredients listed are sugar, liquid glucose, milk solids, cocoa solids, hydrogenated vegetable oil (HVO), vegetable fats, malt extract, soya solids, permitted emulsifier, salts, buffering agents, permitted stabilizer, sodium bicarbonate, cocoa butter,

wheat flour, edible starches, vegetable oil, added flavor, soya lecithin, yeast and flour improvers, etc. Out of the above- mentioned ingredients, milk solids, cocoa solids, cocoa butter, hydrogenated vegetable oil, vegetable fats, permitted emulsifier, buffering agents and permitted stabilizer may be the source of nickel, lead and cadmium contamination.

3. Nickel, lead and cadmium contents were determined in 69 different brands of chocolates and candies available in local markets of suburban areas of Mumbai, India. The majority of these chocolates and candies are made mainly from cocoa, milk solids, dry fruits, fruit flavors and sugar. Out of 69 brands of chocolates and candies analyzed, 23 were cocoa-based, 22 milk-based and another 24 were of fruit flavor and sugar-based. Cadmium level ranged from 0.001 to 2.73m g/g with an average of 0.105m g/g. Nickel ranged from 0.041 to 8.29m g/g with an average of 1.63m g/g and lead level ranged from 0.049 to 8.04m g/g with an average of 0.93m g/g. Cocoa-based chocolates are found to have higher contents of the analyzed heavy metals than milk-based chocolates, fruit flavor - or sugar-based candies.

4. Since it is added in comparatively smaller amounts, it is considered quite insignificant from the health’s point of view. However, it has been reported that eating chocolates with nickel greater that certain amount might cause premature graying of hairs. Deposition of nickel in significant amount can pose a major health hazard in the body.

IMPORTANT ROLE OF NICKEL1. NICKEL is added to chocolates for increasing

their melting point and for preventing and for preventing it from melting at normal temperature.

2.Carrying out systematic qualitative analysis and quantitative analysis can identify presence of nickel by precipitating Nickel Di-methyl glyoxime.

ROLE OF NICKEL IN HUMANS1. The ever increasing presence of nickel in

nature and human food has made it the subject of growing interest of research workers in various medical disciplines. Its allergizing, toxic, mutagenic and carcinogenic causes justified concern of those who use it in orthopaedics and stomatology. The frequency of contact allergy to nickel has called attention to its use in production of many daily utility objects. The probability of allergy is not limited only to persons with occupational exposure to this element but it becomes ever more widespread in the whole population.

2. The role of nickel in contact allergy is well known, and a particular feature of this allergy is the character of allergens which are simple happens with respect to their antigenic. More detailed data on the mechanism of contact allergy have been provided by the discovery of Langerhans cells which have the ability of antigen presentation. Considering the role of nickel in pathological conditions we must not forget its great physiological importance as a microelement necessary for life.

3. About 0.02% micron molecule of nickel is present in human serum. Is it believed it is involved in stabilizing the RNA structure. It also play role in functioning of enzymes oxidoreductases tranferases (like urea).

TOXICITY OF NICKEL

1.Toxicity has occurred in workers exposed to nickel dust or nickel carbonyl formed in refining. Increased risk of nasal and lung cancers was linked to occupational nickel exposure before current workplace safety standards were set. Environmental sources of lower levels of nickel include tobacco, dental or orthopedic implants, stainless-steel kitchen utensils and inexpensive jewelry. Repeated exposures may lead to asthma and contact dermatitis, symptoms of which may worsen if the diet is high in nickel. The oral toxic dose is about 1000 times the amount consumed in food.

2.Different chemical forms vary widely in toxicity. Excessive nickel in tissues is pro-oxidant (damaging chromosomes and other cell components) and alters hormone and enzyme activities, movement of ions through membranes, and immune function. These effects can change glucose tolerance, blood pressure, response to stress, growth rate, bone development and resistance to infection. Under some conditions, large amounts of nickel may precipitate magnesium deficiency or cause accumulation of iron or zinc.

3. NICKEL can cause dermarits (occupation), lungs and nasal caranomas, liver necrosis, pulmonary inflammation. This work has been done in view of the toxic effects of these heavy metals and their presence in chocolates, which can be deleterious to children. The present study reports concentration of lead, nickel and cadmium in the chocolates and candies available in suburban areas of Mumbai, India.

NICKEL’S PROPERTIES1. NICKEL is transition elements with atomic

number 28 and has the configuration

1s2 2s2 2p6 3s2 3p6 4s2 3d8

2. As it has two unpaired electrons so it is paramagnetic. Since there is partly filled orbital it exhibits various properties like variable oxidation status, colored ions. Catalytic properties but must important is formation of complexes.

3. Nickel is silvery-white, Hard, malleable, and ductile metal. It is of the iron group and it takes on a high polish. It is a fairly good conductor of heat and electricity. In its familiar compounds nickel is bivalent, although it assumes other valences. It also forms a number of complex compounds. Most nickel compounds are blue or green. Nickel dissolves slowly in dilute acids but, like iron, becomes passive when treated with

HNO3

AIMTo identify nickel and estimate the amount of its presence in the chocolate .

CHEMICALS REQUIRED1. Dilute Hydrochloric acid {HCl}2. Ammonium hydroxide {NH4OH}3. Ammonium chloride {NH4Cl}4. Dimethyl glyoxime5. Hydrogen sulphide {H2S}

APPARATUS1. Test tube2. Stand

3. Test tube holder4. Dropper 5. Spatula6. Watch glass

Procedure

1. Take a few pieces of chocolate in a test tube. Add dilute HCl to dissolve it. Apply usual chemical test to confirm the presence of Nickel in it.

2. For quantitative estimation take a weighed amount of Chocolate in a beaker. Add Dilute HCL and shake it till it few amount of chocolate dissolves. Filter the solution and add sufficient amount Dil. HCl and pass H2S gas. Thus ppt. is not obtained.

3. Add NH4Cl and NH4OH in the solution and pass H2S gas to it. Black ppt. is obtained which shows the presence of Nickel in it.

4. Make a sample solution add NH4OH & NH4Cl and few drops of Dimethyl glyoxime where it shows presence of Nickel by reddish colour with ppt.

OBSERVATIONQUALITATIVE ANALYSISS.NO

EXPERIMENTS OBSERVATION INFRENCE

1 Sample +dil. HCL Sample doesn’t dissolves

Absence of 1st group

2 Sample solution +dil. HCL. Pass H2S gas

Ppt. not obtained Absence of 2nd group

3 Boil off H2S gas. Add NH4CL and NH4OH in solution

Ppt. not obtained Absence of 3rd group

4 Pass H2S gas Black ppt. is obtained

Group IV is present {Ni2+ or CO2+

}5 Sample solution

+NH4OH +Di-methyl glyoxime

Red rose ppt. is obtained

Presence of nickel

CONCLUSIONNICKEL is present in the given chocolate.

REACTIONNickel is confirmed by formation of bright red ppt. with DMG NiS + 4H+ + Cl- + NO3+ Ni2+ + S +NOCl + 2H2O Ni2+ + 2C4H8N2O2 (aq) Ni (C4H7N2) O2 (S) +2H+

RESULT

S.NO SAMPLE PRESENCE OF NICKEL

1. Dairy Milk shots Present2. Dairy Milk Present3. Kit Kat Present4. Bar one Present5. 5 Star Present

PRESENCE OF NICKEL IN GIVEN SAMPLES IN DECREASING ORDER

BAR ONE > KIT KAT > 5STAR > DAIRY MILK > DAIRY MILK SHOTS

CONCLUSIONThe chocolate contains nickel in varying amounts though it’s not shown by the taste

BIBILOGRAPHY

1. N.C.E.R.T chemistry book2. Comprehensive chemistry lab manual3. GOOGLE4. SCRIBD.COM