Chemical composition of colemanite is:

1. Ca₂B₆O₁₁.5H₂O
2. CaB₄O₇.4H₂O
3. Na₂B₄O₇.4H₂O
4. CaNaB₅O₉.8H₂O
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Answer: A
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Which element forms an ion with charge⁺³:

1. Beryllium
2. Aluminium
3. Carbon
4. Silicon
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Answer: B
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Which electronic configuration corresponds to an element of group3-A of the periodic table

1. 1s²,2s²,2p⁶,3s²3p¹
2. 1s²,2s²,2p⁶,3s²,3p⁶,4s⁶
3. 1s²,2s²,2p⁶
4. 1s²,2s²,2p⁶,3s²,3p³
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Answer: A
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Which element among the following belong to group 4-A of the periodic table?

1. Barium
2. Iodine
3. Lead
4. Oxygen
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Answer: C
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Boric acid cannot be used:

1. As antiseptic in medicine
2. For washing eyes
3. In soda bottle
4. For enamels and glazes
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Answer: C
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Which of the following elements is not present abundantly in earth’s crust?

1. Silicon
2. Aluminium
3. Sodium
4. Oxygen
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Answer: C
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Tincal is a mineral of:

1. Al
2. B
3. Si
4. C
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Answer: B
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In group V-A elements the most electronegative elements is

1. Sb
2. N
3. P
4. As
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Answer: B
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The brown gas formed when metal reduces HNO₃ is

1. N₂O₅
2. N₂O₃
3. NO₂
4. NO
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Answer: C
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Laughing gas is chemically

1. NO
2. N₂O
3. NO₂
4. N₂O₄
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Answer: B
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