Environmental Engineering

151.Presence of _________ hardness is responsible for the temporary hardness in water.

1. Carbonate
2. Calcium
3. Chloride
4. Sulphate

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152.Presence of _________ in water stream are deleterious to aquatic life.

1. Soluble and toxic organics
2. Suspended solids
3. Heavy metals and cyanides
4. All (A), (B)&(C)

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153.Presence of a certain minimum quantity of fluorine is desirable in potable water to prevent

1. Dental cavities
2. Scale formation
3. Water-borne disease
4. Corrosion

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154.Presence of bacteria in potable (drinking) water causes

1. Turbidity
2. Disease
3. Bad odour
4. Bad taste&colour

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155.Presence of carbon monoxide in atmosphere produced by decomposition of chlorophyll and haemoglobin breakdown of some animals, beyond TLV (>50 ppm)

1. Acts as a green house gas thereby raising earth's temperature
2. Causes asphyxia
3. Causes increase in sea level
4. Enhances the green house effect

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156.Presence of dissolved impurities of _________ is responsible for the red brownish color of water.

1. Carbonates
2. Bi-carbonates
3. Iron&manganese
4. Arsenic

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157.Presence of excess fluorine in water causes

1. Dental cavity
2. Tooth decay
3. Fluorosis
4. Respiratory disease

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158.Presence of high concentration of ozone and smog in atmospheric air causes the

1. Embrittlement&decrease of folding resistance of paper
2. Cracking of rubber products
3. Fading of dye on textiles
4. Damage of electrical insulator on high tension power line

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159.Presence of iron and manganese in water causes

1. Reduction in its dissolved oxygen content
2. Discoloration of bathroom fixtures
3. Temporary hardness
4. None of these

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160.Presence of nitrates in water in excess of 50 ppm causes

1. Methemoglobinemia
2. Gastroenteritis
3. Asphyxiation
4. Tooth decay

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