CHEMCO Exit Exam • Set 1 Question 6 of 30

What is the key limitation of Zinc Silicate tank coatings in chemical tankers?

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Direct Answer

Option B: Incompatible with acids and strong alkalis (pH limits usually 6 to 10)

Zinc silicate reacts with acidic or strongly alkaline solutions, destroying the coating matrix.

All Options

Highly flammable surface coating

Incompatible with acids and strong alkalis (pH limits usually 6 to 10) (Correct Answer)

Cannot handle aromatic solvents like Benzene

Melts at room temperature

Detailed Explanation & Context

Zinc silicate reacts with acidic or strongly alkaline solutions, destroying the coating matrix.

Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • Advanced Training for Chemical Tanker Cargo Operations (CHEMCO).

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More Questions in CHEMCO Set 1

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Q1 Which IMO Code regulates the carriage of dangerous chemicals in bulk on chemical tankers? Q2 Under MARPOL Annex II, which pollution category presents the major hazard to human health or marine resources? Q3 What test is performed on tank bulkhead surfaces to detect microscopic hydrocarbon residues before loading sensitive chemical cargoes? Q4 What type of chemical tanker skin/tank construction is required for carrying high-hazard cargoes like Isocyanates? Q5 What material is widely used for cargo tanks carrying aggressive acids such as Nitric or Phosphoric acid? Q6 What is the key limitation of Zinc Silicate tank coatings in chemical tankers? Q7 What document must be maintained on board detailing all chemical cargo loading, discharging, tank washing, and slop handling? Q8 What is self-polymerization in chemical cargoes? Q9 What mandatory document provides chemical property, health hazard, reactivity, and emergency response data for a chemical cargo? Q10 What system is used to purge chemical lines and maintain an inert nitrogen cushion over moisture-sensitive cargoes?